For detection of carriers of Duchenne muscular dystrophy the calf musculature was investigated for increased fat and connective tissue content using ultrasound. The investigation was done blind in 24 females without prior information on family history and creatine kinase (CK-)values. In 5 out of 6 carriers and in 5 out of 7 controls the correct diagnosis was made. One carrier was assumed to be unaffected and in two controls findings were inconclusive. Out of 11 potential carriers with normal CK-values 4 were considered to be carriers. One borderline case could not be assigned clearly. For the present problem ultrasound diagnostics have been proven to be useful particularly in older females in whom enzyme assessment will not produce pathological data.