This is a list of fictional diseases, named medical conditions that do not exist. These include naturally evolved, accidentally man-made or intentional biological weapons. Also, a brief pathology is included for these fictional illnesses, where appliciable.

• AMPS (Acquired Melanin Production Syndrome) - sexually transmitted, genetically engineered disease that turns white people black, Good News From Outer Space, by John Kessel
• Andromeda - airborne pathogen, unknown organism, extraterrestrial origin, causes fatal blood clotting, Andromeda Strain
• Barclay's Protomorphosis Syndrome - a disease that apparently re-activates pseudogenes, resulting in physical "devolution" to earlier phenotypes. Named after Reginald Barclay in whose body it was inadvertently created, Star Trek: The Next Generation
• "The Big Death" - airborne pathogen, virus, biological weapon, notable for its high lethality amongst persons over the age of puberty, Jeremiah
• Boneitis - fatal, non-contagious, affliction of the bones, Futurama
• "Captain Trips" - virus, The Stand
• Cyberbrain Closed Shell Syndrome - a type of autism caused by cyberbrain implants, Ghost in the Shell: Stand Alone Complex
• Cyberbrain Sclerosis - cyberbrain implant malady resembling multiple sclerosis, eventually fatal, Ghost in the Shell: Stand Alone Complex
• Drafa Plague - Babylon 5
• Dreaming Death - killed characters on the soap opera Guiding Light
• DR SAM - A drug-resistant staphylococcus strain in Anne Benson's The Plague Tales novels.
• Entitilitus - "Nobody knows what entitilitus is, but entitilitus kills", Mr. Show
• Fairy Flu - causes fairies to lose control of their magical powers, The Fairly Oddparents
• Foaming Sheep Sickness - disease caused by eating green mutton in the Discworld novel Jingo, a parody of Mad Cow Disease.
• Glaubner's disease - Firesign Theatre
• Gray Death - Deus Ex
• Homer Simpson Syndrome - Homer Simpson: "Oh, why me?"; genetic condition, causes cerebral fluid to be 1/8" thicker than normal, cushioning the brain like a helmet, perhaps at the cost of some mental faculties, The Simpsons
• Human Metahuman Vampiric Virus (HMHVV) - blood-borne pathogen, virus, known to produce vampires, wendigoes and other abominations, Shadowrun role playing game
  • Krieger strain - strain of HMHVV, with similar contagion, but produces cannibalistic ghouls, also Shadowrun
• Imminent Death Syndrome (IDS) - sufferers are "on the brink of death for 80 to 100 years", Mr. Show
• Jigsaw disease - terminal disease that causes random parts of the body to spontaneously vanish, from the Judge Dredd comics
• JUVE - biological weapon developed by Crake, distributed initally in a dormant form via his BlyssPluss pills, symptoms include necrotizing flesh and extreme hemorrhaging to organs, Oryx and Crake
• Magnimus Obliviophallocytis a.k.a "Little Donny Disease" - hereditary, enlarged genitalia, Upright Citizens Brigade
• Martian venereal disease - untreatable infection rare on Earth (except among certain City prostitutes), Transmetropolitan
• Metastatic Human Cancer Virus - causes unusual cancer that can not be killed, but can be removed, and, despite name, can infect animals and even plants, Loop by Koji Suzuki
• Motaba virus (named for the Motaba River) - causes hemorrhagic fever in humans similar to that of Ebola, a later strain was found to be airbourne, Outbreak
• Necrotizing fasciitis - An actual disease; however, when it was featured in the movie Cabin Fever, it had a drastically accellerated and amplified effects.
• Nerve Attenuation Syndrome (NAS), a.k.a. "the Black Shakes" - environmental attributed cause, increased seizures to the point of death, Johnny Mnemonic
• Noocytes - genetically engineered lymphocytes, highly intelligent and capable of altering genetic material, Blood Music
• Pecanitis - from CatDog, affects dogs who eat pecans; can take effect in a variety of ways. In Dog's case, it causes a large pecan tree to grow out of his head.
• "The Phage" - disease which destroys the genetic and cellular patterns of the Vidiian race in Star Trek:Voyager
• Planets - a rare magical disease on the Discworld, the most obvious symptom of which is small planets orbiting the victim.
• "The Rage" - blood-borne pathogen, virus, possible biological weapon, causes uncontrollable rage within seconds of exposure, 28 Days Later
• Recalcitrant plebney - invented by Don Martin of Mad Magazine
• Rigellian fever - from the "Requiem for Methuselah" episode of Star Trek
• Senga - sexually transimitted disease in But'n'Ben A-Go-Go by Matthew A. Fitt
• Solanum - A virus which causes infected humans to become zombies, The Zombie Survival Guide: Complete Protection from the Living Dead by Max Brooks
• Suds - a illness contracted by SpongeBob SquarePants (and presumably other sponges) instead of the common cold. Has many of the same symptoms as a cold, except that when sneezing takes place, soapsuds come out of his pores. Can be cured with the "sponge treatment" (using the sponge for cleaning jobs), SpongeBob SquarePants
• Symbalene blood burn - causes the vascular lining of blood vessels to boil away, Star Trek: Enterprise
• Syphon Filter - an artificial virus described as "the ultimate bioweapon" because it can be genetically programmed to target any ethnicity. Featured in the video game series of the same name.
• Tumorsyphilisitisosis - a fake fictional disease which causes extra nipples, which look remarkably like pepperoni, to grow and then fall off. Conceived by Peter Griffin as part of a brilliant scheme to get a canceled television program back on the air, Family Guy
• T-Virus - virus, causes dementia and cellular necrosis, mutates easily into other strains, which often have mutagenic effects on the host, Resident Evil
• Vegan choriomeningitis - contagious pathogen from Vega, usually fatal, from "The Mark of Gideon" episode of Star Trek
• Venereal ergot infection - produces uncontrollable hallucinations and delirium, Transmetropolitan
• Virally Induced Toxic Allergy Syndrome (VITAS) - airborne pathogen, virus, possible biological weapon, Shadowrun role playing game
• Wasteland Herpes - sexual transmitted disease, radiation-mutated form of herpes, prevalent in prostitutes in post-WWIII Nevada, Wasteland computer game
• Weasles - "bio-artificed" disease, apparently related to Mustelidae somehow: "We're talking boils that really bite." Mentioned in the Discworld novel Thief of Time
• Zombie contagion - in the 2004 remake of Dawn of the Dead, a person could only become a zombie after being bitten by another zombie, showing that whatever caused the dead to rise could only be passed through fluid contact. This makes the epidemic more disease-like in nature than the outbreaks in George A. Romero's original Dead Trilogy, in which any dead body could become reanimated.