There are some indications that Becker muscular dystrophy (BMD) might be related to mental disorders and mental retardation (MR). To investigate this question, we made a standardized psychiatric and intellectual level assessment of 22 BMD patients in comparison with 22 limb-girdle muscular dystrophy (LGMD) patients. There were not significant differences between the two groups. Twelve patients (54.5%) in each group received at least one lifetime psychiatric diagnosis, the most frequent being depressive disorders. The intelligence quotient means for BMD was 85.9 and 87.8 for LGMD. There was one case of mild MR among BMD patients and two cases among LGMD patients.