The authors analyze the effectiveness of the National Vaccination Programme with regard to poliomyelitis eradication in Bulgaria and the difficulties encountered in the 1980s and at the beginning of the 1990s. An account is presented on the eradication achieved, interrupted by an outbreak of 46 cases in 1991. The critical analysis points out the negative influence of several factors, disrupted by the failure in 1991. Based on these fact conclusions are drawn on a prolongation of the period needed to achieve the Eradication Programme goal. The main reasons for the delay are as follows: the intensive migration process, the existence of small non-immunized groups of population (gipsy population) as well as some shortcomings in the organization of the health services. According to the authors, stricter epidemiologic supervision is imperative for the country as well as coordination of similar approach to the problem in countries of the region.