Thirteen Canadians with a mild hypochromic anemia were found to have beta thalassemia trait. The families of these individuals had resided in Canada for two to five generations and, where known, had not emigrated from areas with a high incidence for the thalassemia gene. A Negro family with abnormal erythrocyte morphology was suspected to be carrying the thalassemia gene although the hemoglobin A(2) concentration was normal and abnormal minor components were not detected. Thalassemia trait has been detected in practically every ethnic group, and its sporadic occurrence among Canadians without Mediterranean ancestry can be expected.