1. Renal function was impaired both in Ancylostomiasis and Necatoriasis. 2. Impairment of renal function was severer in Ancylostomiasis than in Necatoriasis. 3. Positive relation between degree of infection and of impairment of renal function was proved in Ancylostomiasis, but not in Necatoriasis. 4. Positive relation between anemia and impairment of renal function was proved both in Ancylostomiasisand Necatoriasis. 5. Renal function showed a recovery after treatment.