The aim of this work was to study the presence of mycobacteria in tissue samples from four cadavers fixed with formalin, and tissue samples from a recently deceased unpreserved individual, who had a history of human tuberculosis infection, undergoing a post mortem (cause of death not related to tuberculosis). All were examined for the presence of tuberculous lesions and the specific presence of Mycobacterium tuberculosis complex (MTC) and M. avium complex (MAC) members by microscopy, culture, and PCR analysis of four genomic elements (IS6110, mtp40, IS901, and IS1245). Microscopy examination after the Ziehl-Neelsen staining and culture examination for the presence of mycobacteria were negative in all 22 tissue samples from the four embalmed cadavers. PCR analysis of IS6110 and mtp40 was positive in tissue samples of tuberculous lesions from the lungs of two embalmed cadavers, and from intact kidney tissue of one of these cadavers. Microscopy and culture examinations of liver and spleen tissues from the unpreserved cadaver were positive for mycobacteria. PCR analysis, specific for M. avium subsp. avium, was positive in both tissue samples with, and without tuberculous lesions.