The approach to treatment of visceral leishmaniasis (VL)-HIV co-infection in East Africa has not been systematically examined. Although antiretroviral treatment (ART) should be initiated for all co-infected persons, the extent of ART prescription is not known. We conducted a retrospective cohort study including all VL-HIV co-infected adults at selected referral and district hospitals in northwest Ethiopia from 2010 to 2015. Purposes of the study were to compare the proportion of VL diagnoses made in previously diagnosed HIV-patients versus diagnosis concurrent with HIV diagnosis and to quantify utilization of ART. We included 112 patients and 58 patients at the referral and district hospital, respectively (median age: 30 years, 98% males). Of all VL cases, 56% (63/112) and 19% (11/58) occurred in known HIV patients at the referral and district hospital, respectively, with a median CD4 count at VL diagnosis of 45 cells/µL and 248 cells/µL at the referral and district hospital, respectively. Seventy-six percent (56/44) were on ART at VL diagnosis and nine (12%) started ART after VL diagnosis. The remaining 96 (56%) patients had both infections diagnosed concurrently, with a median CD4 count of 56 and 143 cells/µL at the referral and district hospital, respectively. Among cured patients, ART initiation was 67% and 36% at the referral and district hospital, respectively. A substantial proportion of VL-HIV cases occur while in HIV care, requiring further evaluation of preventive strategies. Among newly diagnosed VL-HIV co-infected patients, ART initiation was low. The reasons, including poor documentation and information exchange, should be assessed.