OBJECTIVES: Recognition and identification of bone fragments are of primary importance to confirm or exclude the human origin of skeletal remains. When badly degraded fragments of bone are found, this may be impossible by gross morphology alone, and histological methods have to be used. Aim of this study is to correlate the compact bone tissue microstructure in various classes of mammals, including humans, and birds in order to find an adequate identification key. MATERIALS AND METHODS: We used long bone diaphysis samples. Bone fragments had been fixed in 4% formalin and then decalcified in EDTA (ethylene-diamin-tetra-acetate). After decalcification, samples had been processed for routine paraffin inclusion. Transverse sections had been cut and stained with hematoxylin-eosin staining, and examined by light microscopy (Nikon Eclipse E400®). RESULTS: The results of our study show that in bone tissue samples from various classes of mammals, including humans, and birds the osteonic structure shows peculiar features, often depending on the rate of bone remodeling, different in different animal species. CONCLUSIONS: We conclude that a careful microscopic analysis of bone tissue and the characterization of distinctive osteonic features could give a major contribution to forensic medicine to obtain a more reliable recognition of bone fragments of unknown origin.