Abstract A description is provided for Candida tropicalis . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Candida tropicalis is an opportunistic pathogenic regularly implicated in candidosis in man and animals. The disease process, generally restricted to the compromised host, is similar to that caused by C. albicans and includes meningitis, endocarditis, acute disseminated candidosis, pyelonephritis, oesophagitis and vaginitis in man, with bovine mastitis and mycotic abortion occurring in animals. Candida tropicalis has been isolated from a variety of warm-blooded animals but rarely from the environment and has been isolated from the gut, vagina and oral cavity of humans indicating that the organism occurs as a commensal of these sites. Such results are, however, difficult to interpret since results vary greatly from study to study and most results have been obtained from hospitalized patients (see Odds, 1969). Pathogenicity experiments have shown that Candida tropicalis is the second most virulent Candida species (second only to C. albicans ). Numerous studies have shown the organism to cause fatal disseminated infection in laboratory animals following intravenous inoculation, although there is some discrepancy as to the level of pathogenicity in unmodified hosts. Hurley obtained 100% mortality in normal mice following intravenous inoculation of 2.5 × 10 cells (in Winner & Hurley (eds), Symposium on Candida Infections , London: E. & S. Livingstone Ltd, pp. 13-21, 1966). Kennedy & Voltz, however, obtained gut colonization and dissemination to visceral organs in antibiotic treated mice following intragastric inoculation of 10 organisms but no colonization of untreated mice ( Sabouraudia 21: 27-33, 1983). For other literature on pathogenicity see Odds (1979). GEOGRAPHICAL DISTRIBUTION: Probably worldwide. Africa (Algeria, Congo, Egypt, West Africa, Ivory Coast, Madagascar, Mauritius, Nigeria, Somalia, Sudan, S. Africa); Asia (Bangladesh, China, Hong Kong, India, Iran, Iraq, Japan, Kuwait, Lebanon, Philippines, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam); Australasia and Oceania (Australia, New Zealand, Cook Islands, Fiji, Tahiti); Europe (many countries); North America (Canada, Cuba, El Salvador, Mexico, USA); South America (Argentina, Brazil, Chile, Colombia, Guyana, Peru, Uruguay, Venezuela).