Purpose of review: Epidemic sporotrichosis is rare and has been related to an environmental source of infection. There were no reports of epizootics before a cat-transmitted epidemic was reported in Rio de Janeiro, Brazil. In the present paper we review the data published on this epidemic. Recent findings: From 1998 to 2004, 759 humans, 64 dogs and 1503 cats were diagnosed with sporotrichosis in the Evandro Chagas Clinical Research Institute. Of them, 85% of dogs and 83.4% of patients were reported to have had contact with cats with sporotrichosis, and 55.8% of the latter reported cat bites or scratches. Unusual manifestations were diagnosed in humans. Canine sporotrichosis presented as a self-limited mycosis. Feline sporotrichosis varied from subclinical infection to severe systemic disease with hematogenous dissemination of Sporothrix schenckii. Sporotrichosis in cats always preceded its occurrence among their owners and their domiciliary canine contacts. The zoonotic potential of cats was demonstrated by the isolation of S. schenckii from skin lesion fragments, and from material collected from their nasal and oral cavities. Summary: Thus far it is not known why sporotrichosis takes on the proportion of an emergent zoonosis in Rio de Janeiro. We alert physicians and veterinarians working outside the epidemic area to the diagnostic challenges involved with sporotrichosis.