Urinary schistosomiasis is a common cause of hematuria in tropical regions, where it most often affects teenage boys. Children presenting with hematuria in the developed world are usually considered to have bacterial cystitis or a structural lesion and are investigated and treated accordingly. The authors report on a family recently returned to Canada from Nigeria in which all four children had urinary schistosomiasis. Nocturnal enuresis was the presenting symptom in the index case; this patient also had hematuria and dysuria. Nocturia occurred in a second child, and the other two children were asymptomatic. All four were cured by a single dose of praziquantel, a new schistosomicide. The life cycle of the causative organism, the clinical manifestations of schistosomiasis, the host response and treatment with praziquantel are reviewed.