Thirty Ethiopian malnutrition-related diabetes mellitus (MRDM) patients were HLA typed and their HLA antigen frequencies were compared to those of 31 previously typed insulin-dependent diabetes mellitus (IDDM) patients and to 84 controls from the same ethnic background. In comparison to controls, a striking association between MRDM and HLA-DR3 (X2 = 15.15, p = 0.0001) was observed, whereas the frequency of HLA-DR4 was non-significantly increased (RR = 1.72). The frequency of DR2, DQw1, and DQw6 was decreased among MRDM. In comparison to IDDM that is associated with both DR3 and DR4 in this population, MRDM showed no significant differences in HLA class II antigens frequencies. Therefore, the genetic basis of susceptibility to MRDM and IDMM in Ethiopia is at least partially identical.