The paper presents investigation of efficiency of thromboembolic prophylaxis heparin/dihydroergotamine in patients with femur cervix fracture undergoing standard operational treatment with insertion of partial femur endoprosthesis. Various thrombo-prophylaxis durations have been considered, after the patients have been divided into a control group (without thrombo-prophylaxis) and the group of patients which were subjected to thrombo-prophylaxis for period of up to one week and two, three and four weeks. The investigations have encompassed a rather large group of 162 patients operatively treated within a 12 year period (1974-85) at Orthopaedic Clinic in Biograd o/s. Based on the analysis of general characteristics of standard cases, where thrombo-prophylaxis duration has been examined by statistical methods applied to observed material, and on the basis of comparison with previously published experiences, optimum duration of thromboembolic prophylaxis is proposed.