The performed analysis concerned the results of the histopathological examination of 169 cases of osteogenic sarcomas with reference to diagnostic difficulties. It was found that the most difficult cases belong to the extreme groups of the classification i.e. were high or very low differentiated osteogenic sarcomas. The most difficult diagnostically cases according to the structural classification concern analogically the extreme group of cases of the non-conventional histology. However, the dominant number of the diagnosed cases did not belong to the extreme groups of classification.