Many sources advocate the empiric use of antibiotics to prevent wound infection (WI) following crotalid (rattlesnake) envenomations. We undertook a prospective observational study to examine the incidence of infections following crotalid envenomation. We studied crotalid envenomations presenting to our institution with follow-up by direct examination or telephone consultation. All patients presenting to our institution from June 1990 to October 1991 with history and clinical evidence of crotalid envenomation were included in the analysis. Routine management of crotalid envenomation was undertaken in each case, including the use of antivenin, surgical debridement, and antibiotics only when indicated by signs and symptoms of infection. A total of 54 patients were observed during the study period. Twelve patients received prophylactic antibiotics begun either prior to transfer to our institution or following a surgical procedure, and were evaluated separately. Follow-up was obtained on 32 patients 7 or more days following envenomation. Only 1 patient from the study group developed clinical evidence of WI during the study period. We conclude that because of a low incidence of WI in this series, the routine use of prophylactic antibiotics in such patients may not be warranted.