Abstract.During field studies (December 1988 to April 1990) to determine the vectors of visceral leishmaniasis (kala‐azar) in the Aba Roba (Segen Valley) focus of southern Ethiopia, a total of 40,770 sandflies (Diptera: Psychodidae: Phlebotominae) were collected and identified as six species ofPhlebotomusand seventeenSergentomyiaspp. Nine of these species were anthropophilic (fourPhlebotomusand fiveSergentomyiaspp.), the dominant beingPhlebotomus (Synphlebotomus) martini, P.(S.)celiae and Sergentomyia (Sergentomyia) schwetzi. P. celiaeadult populations increased during the rainy season. Of 2326P. martiniand 1044P. celiaedissected, the parous rate was 29.9% and 24.4%, respectively.Leishmaniapromastigotes were detected in sixteenP. martini(eleven identified asL. donovaniby isoenzyme analysis and/or a DNA probe) and in threeP. celiae(two identified by DNA probe), giving overall infection rates of 0.7% (1.9% parous infection rate) and 0.3% (1.2% parous infection rate), respectively. Four isolates fromP. martiniwere typed by their isoenzyme profile asL. donovanizymodeme MON‐37 = LON‐44, identical to one of the zymodemes isolated from patients in this focus. This is the first evidence thatP. celiaeis a vector and the first time thatP. martinihas been implicated in Ethiopia. Based on observations of abundance, seasonality and prevalence of infection of the twoSynphlebotomusspp., it is concluded thatP. martiniis the major vector andP. celiaea secondary vector in the Aba Roba focus. The risk of infection withL. donovaniis greatest during the wet s