On the basis of the cases registered in the Outpatient Clinic for Muscular Diseases, Medical Academy in Warsaw including patients with progressive muscular dystrophy, and after an analysis of follow-up data the epidemiological indices and mutation indices were estimated in the population of Warsaw, Province of Warsaw and Province of Radom for the years 1960-1976. The calculated indices of incidence and prevalence of dystrophy and mutation were at the upper range of values reported in world literature. They were, however higher than those estimated in previous years in the same regions by Prot. The calculated index of natural abortions in mothers of patients with Duchenne's dystrophy was slightly higher than in the control group of women. Follow-up investigations show that the genetic counselling in this disease was insufficient in that time period.