The Uncommon Common Infected (AKA Uncommon Infected) are new forms of the Common Infected. They have the same general weaknesses and slightly higher health than most Common Infected, but there are a few differences that can affect how they're dealt with. Every campaign has its own unique Uncommon Infected.

Each Uncommon Infected have reflective clothing, helping differentiate them from the regular Common Infected:
◾ The CEDA Worker Infected have reflective areas on their suits.
◾ The Clown Infected wear reflective makeup, which is arguably the least noticeable.
◾ The Mudmen's mud is reflective.
◾ The Worker Infected have reflective vests, which are most noticeable during the storms.
◾ The bands on the Riot Infected's arm, along with the word "Security" on his chest are reflective.
◾ Some Fallen Survivors have reflective bright red medkits on their backs.
These reflective areas can be easily seen by turning your flashlight on.

These Infected appear in the Hard Rain campaign. Workers are equipped with ear protection, hardhats, and reflective vests making them easier to spot in the storm. Their ear protectors stop the noise of Pipe bombs, and their melee (but not shove) resistance is greater than usual. Theyare also immune to Bile bombs that have smashed on a surface. (but only since the bile alone on the ground uses similar programming as the Pipe bomb). They will attack Infected hit by the bile, but will target the Survivors once those Infected are dead. They are the only Uncommon Infected to not have specific lines when spotted by a Survivor, and are also the only Uncommon Infected to appear on every chapter of its campaign. Though they are reported to be a demolition crew, the texture files call them Common_male_roadcrew.

When deaing with workers, the easiest way to kill them is to shoot them. If you are trying to thin out a horde, use boomer bile instead of pipe bombs if you have some. The workers will ignore the Pipe bomb's whining and continue to chase you. On easier difficulties, this doesn't matter much, but on harder settings a group of workers could be devistating. Remember is to check the immidate area after throwing a Pipe bomb to see if any workers are present.

The Worker also appears in the The Sacrifice and the Left 4 Dead 2 ports of No Mercy and Dead Air.

The Clown Infected wander around the Dark Carnival campaign. When they spot Survivors, they will attack like any basic infected, unintentionally calling in other Infected with their squeaky shoes for a mass attack. No new Infected are spawned during these mini-hordes, but a Clown in attack mode attracts Common Infected and other Clowns nearby. If a Clown is killed at range, all Infected following him will stop, mill around his dead body and then attack the Survivors.

Clown pants come in a variety of colors, including pink and blue, red and yellow, blue and white, and white and red as seen in the picture. A shove will honk the Clown's false nose.

When Clowns are giving you trouble, try to use the grouping of infected behind him to your advantage. (Fire usually works well). Clowns also make mowing down infected easier, as they are all in close proximity to one another rather than spread out. If one survivor is really brave, he could get a Clown to chase him, backtrack through the map and lure a huge horde miles away from the other surivors. However, this could leave him open to special infected attacks, and should only be used in dire situations.

The Mud Men inhabit the swamp in the Swamp Fever campaign. They are similar to the Common Infected, except that they are covered in mud camouflage. Mud men sprint on all fours low to the ground, although they stand on two feet when shoved or stumbled. Their 'sprinting crawl' allows them to travel at a faster speed than the Common Infected can, and they are not slowed down by water. A hit from a Mud Man covers part of the player's screen with mud, and the mud on their screen increases with successive hits, blurring the screen like Boomer Bile. The Mud Man's movement is rather strange, but actually exists in Left 4 Dead: If a player enters an area that requires them to crouch (air vent, under boxes, and so on), the Infected will follow them in, but will crawl on all fours to get to them. Note that mudmen can actually appear from the MUD rather than from a spawn area.

A Mudman should be dealt with like A Hunter or Jockey: Using a weapon suited for small or hard-to-target infected, like a shotgun or magnum. If you get trapped in the mud, you could easily lose most of your health to a horde of mudmen if you don't deal with them quickly.

Mudmen also appear in the ports of Death Toll and Blood Harvest, despite there not being any muddy swamp areas.

The Riot Cops appear only in The Parish and a small portion of No Mercy. They were members of a private security firm hired to protect civilians. They got infected while still wearing their armor, giving immunity to bullets and to melee attacks from the front, but not from behind. However, They are vulnerable to Chainsaws, and they are still damaged by fire and explosions. Riot Infected have a chance to drop the Nightstick melee weapon.

They don't have any Achievements linked to them, as they were originally cut in the German and Australian version of Left 4 Dead 2. They appear in the Zombie Survival Guide Trailer, oddly in both the regular and censored versions. Riot Cops were first featured in the demo and were censored in Germany due to "violence against authority figures". As Valve used the German version for the Australian release, they also suffered the unneeded cut. However, they have been recently patched back into both versions, having the word "SECURITY" removed from the front of their armor.

When fighting a Riot Cop, the easiest way to take him down is to shove him. HOWEVER, don't shove him in the center mass, as this will push him back, meaning you will have to circle him to get a good shot in the back. Shoving him in the arms or side of the body will make him spin and probably fall down, allowing you to hit him in the back without needing to move. Incendiary ammo will burn the Riot Cop Infected just like how a Molotov would. Explosive ammo will kill the Riot Infected in a few shots even from the front. No regular guns will penetrate the armor and will require a shot to the back to kill them.

If you are playing the Headshot! mutation, they can be a pain to deal with due to the back of their head being the only vulnerable area.

CEDA workers are the first Uncommon Infected that were announced and appear in the Left 4 Dead 2 campaign, Dead Center. Players will occasionally come across Common Infected wearing a hazmat suit, which was worn prior to the person being Infected. When killed, there is a chance of them dropping a Bile Bomb. When shot in the face, blood will splatter across the visor, and the sound of air hissing out of their now-punctured hazmat suit can sometimes be heard. Through development of Left 4 Dead 2, the campaign the CEDA Worker Infected appeared in changed from The Parish, to extend to Dead Center, to being removed from The Parish completely, having been replaced by the Riot Cop Infected.

Due to their hazmat suits, they are resistant to fire, as in they do not burn when hit by a Molotov, and incendiary ammunition just ricochets off them. If idle within fire for a long time, they will die due to the heat. They come in two different varieties: yellow suits and green suits. There were also white suits, but these were only seen in the "Survival" trailer or spotted as ragdolls scattered about certain areas of the campaign, "The Parish".

If you look closely at the CEDA Worker Infected, you will notice that the gloves are on the inside of the suit and the boots aren't part of the suit. This means the suit is not sealed, proved by the fact that they can smell Bile bombs. This might be the reason they were infected.

Fighting CEDA Workers is as simple as shooting them.

The Fallen Survivor was a fairly well-equipped Survivor from the initial outbreak, but apparently became Infected later on. He appears in The Passing wearing three ammo belts with a strap carrying visible items. He will run from Survivors if shot, thus making him the least threatening Infected. However, he will attack if you are covered in Bile or have not shot him.

Unlike Common Infected, he has an extremely high amount of health, being able to withstand multiple point-blank shotgun blasts. The only ways to kill him in one hit are explosive rounds, melee weapons, the M60 or headshots. Headshots are very difficult because you must actually hit his head or his helmet will deflect the bullet and cause no damage, making him run. He is not immune to the lure of Bile bombs or Pipe bombs; if a Survivor uses one, the Fallen Survivor will run to the location it is used.

He was going to be in Left 4 Dead 2 from the start, but was cut from the final version due to people having trouble in the beta version with him, but he was re-added with The Passing. His character model is nearly identical to that of Whitaker, the survivor from Dead Center. He can also be seen in the "Zombie Survival Guide", running towards The Plantation. He has been seen wearing a blue, red, and green shirt.

A Fallen Survivor can carry Molotovs, Pipe bombs, Pain pills and First aid kits, which can be randomly dropped upon his death. Other than The Passing, he appears in the ported versions of Death Toll and Blood Harvest.

Killing a Fallen Survivor is hard, normally requiring you to keep him shoved down and shooting or meleeing him until he dies. Don't bother with him if your team is fully-stocked.

Jimmy Gibbs Junior was a race car driver and an idol to Ellis and Coach. The Survivors steal his race car to escape the mall. He is dressed in his racing suit and only spawns in the Dead Center chapter The Atrium, with a 5% chance of spawning at all. He may be another play on the remake of the movie Dawn of the Dead, where the Survivors could see Infected versions of famous people that they knew from the mall.

Jimmy has 1000 HP, cannot have his limbs severed, and is fireproof. He can also blind players with motor oil (similar to the Mudmen's splatter effect) and is not drawn to Pipe bombs or Bile bombs. Despite the fact that Jimmy Gibbs Junior has 1000 HP, he can instantly be killed by a headshot or a melee attack. This is probably to balance him, but also makes logcal sense: he doesn't have a helmet and his suit isn't armoured.

Jimmy Gibbs Junior is the rarest of all Uncommon Infected to encounter and the only one that is exclusive to a campaign's finale, appearing in the Atrium Finale with only a 5% percent chance to spawn. A possible explanation for his oil-blinding effect is that he was doing repairs on his cars when he got infected, possibly due to either that he was repairing his car for a show, or that he insisted that only himself should do repairs on his car.

Dealing with Jimmy should be your first priority, as he can cause havoc due to his massive health and annoying blind attack. Use explosives or accurate weapons while constantly moving to wear him down. If you have a melee weapon, you can kill him in one hit, making him as weak as a normal infected. Fire doesn't damage him, so never use flames against him.