Background and Objective: BCG vaccination is used in many countries with a high prevalence of TB to prevent childhood tuberculosis meningitis and miliary disease. Local and systemic sideeffects are associated with BCG vaccine. The most critical reaction is disseminated BCG infection which occurs in mostly immunodeficient patients. Materials and Methods: We performed 4 autopsies during 2001-2003 which were suspected for BCGosis clinically and histologically by presence of granulomatous foci in several organs with acid fast bacilli. The mycobacteria were identified by PCR. Their DNA was extracted from the tissue blocks, identified with primers which were designed to detect the RD1 deletion. Results: We found BCG genome by PCR in 3 out of 4 patients. These patients had acid fast bacilli in special staining. Conclusion: Since BCGosis is a fatal and uncommon disease, occurring after vaccination with numerous complications, its diagnosis is of paramount importance and should be considered in the appropriate clinical setting.