Five cases, who had coxa-femoral-desarticulatur due to lower extremity malignant tumours in the dept. of orthopedics in Istanbul Sorial security Hospital between 1985-1986 were analysed retrospectively .Three of the cases were chondrdsarkomas, one osteosarcoma and the other was malignant aneurysmal bone tumour. Etiological factors, localisation of the tumours and the post-operative care are dissussed in this study.