Infection with Schistosoma haematobium, the causative agent of urinary schistosomiasis is characterized by high levels of specific immunoglobulin (Ig) E and eosinophilia. The primary cytokines driving production of IgE and eosinophilia are IL-4 and IL-5, respectively. In this study, IL-4 and IL-5 production in children from a schistosome endemic area of Zimbabwe were investigated. Blood samples were taken, stimulated in vitro with either mitogen or schistosome antigens and assayed for IL-4 and IL-5 production. These samples produced either IL-4 or IL-5 but rarely both cytokines when blood was cultured in vitro for 24 or 48 h. After 72 h culture in vitro, both cytokines were detected in most samples. These data imply that while IL-4 and IL-5 are both produced by schistosome infected people, they are not necessarily coproduced.