The prevalence and pathogenic role of Cyclospora cayetanensis among 212 subjects (age range = two months to 70 years) in an impoverished community in Venezuela were assessed retrospectively. For identification of the coccidium, modified Ziehl-Neelsen carbolfuchsin staining of formalin-ether concentrates was used. For other pathogenic parasites, iron-hematoxylin-stained smears and formalin-ether concentrates were examined. Cyclospora infections were identified in 13 (6.1%) subjects with a high percentage of asymptomatic carriers (11 of 13, 84.6%). Only two (15.4%) infants had diarrhea and the coccidium as the single detectable pathogenic parasite. The findings suggest that Cyclospora infections are relatively common and often asymptomatic in this region.