A study of the morbidity due to schistosomiasis haematobium was undertaken in 121 children ranging in age from 5 to 19 years, from Kanyamedha Primary School, Kisumu. Of this sample 81% of the males and 42% of the females had Schistosoma haematobium. Proteinuria was detected in 23% of the uninfected children; 54% of those with light infection; 80% of those with moderate infection and 94% of those with heavy infection. Similarly, haematuria was detected in 18% of the apparently uninfected individuals, 64% of those lightly infected, and 76% and 94% of those with moderate and heavy infections, respectively. Three of the 20 children given intravenous pyelography had renal and bladder complications, characterized by hydronephrosis, bladder granuloma, bladder calcification and hydroureter.