ABSTRACT It has been reported from several Caucasian studies that there is an epidemiological association between hepatitis c virus infection and diabetes mellitus. The objective of this study was to determine whether any such relationship exists in a black African population. To determine the prevalence of Hepatitis C virus infection in Nigerians with diabetes mellitus in North-Eastern Nigeria. Hospital -based cross-sectional study. Medical out-patient clinic and the Blood bank of the Federal Medical Centre, Yola. Nigeria. From June, 2008 to December 2009, Two hundred and eighty consecutively recruited diabetes mellitus patients comprising 108 males and 172 females were screened for HCV infection. These were compared with five hundred and ninetyfive voluntary blood donors who were screened during the same period. Serological testing for HCV infection was carried out with anti-HCV using Enzyme Linked Immuno-sorbent Assay (ELISA) method. The bio-data of the patients, history and duration of diabetes mellitus, history of jaundice, blood transfusion were recorded on a proforma. Out of the 280 diabetes mellitus patients tested, twenty-six were positive for anti-HCV antibodies giving an infection rate of 9.3% compared with fourteen subjects out of 595 voluntary blood donors 2.4% (p=0.0000105). History of blood transfusion, and jaundice was positively correlated with presence of HCV infection in diabetic patients. Hepatitis C virus is more common in Nigerian patients with diabetes mellitus than in non-diabetic control subjects. It may be necessary to screen patients with diabetes mellitus for hepatitis c virus infection particularly those with history of blood transfusion and jaundice