A clinico-epidemiological study of cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL) was undertaken involving 1,809 residents of ten representative villages from Zeway-Langano, Wajifo-Mirab-Abaya and Blate-Dimtu areas in the middle course of the Ethiopian Rift Valley from November 1994 to June 1996. Community prevalence of positive leishmanin skin test (LST) was very low ranging from 5% in Olge village to 0% in Kello-Langano area. Sera collected from 57 clinical VL suspects originating from the different villages tested negative for anti-leishmanial antibodies. The rate of splenomegaly ranged from 5% in Kello-Langano area to as high as 80% in Korga village. Furthermore, the frequency and size of splenomegaly was related to the reported past and recent history of attack(s) of malaria. The low community prevalence of LST suggests minimal transmission of leishmania infections in spite of the knowledge of the presence of the sandfly vectors of CL and VL in the area. However, with increasing villagization and agricultural development activities, the potential risk for the establishment of VL and/or CL as endemic diseases can not be excluded.