Purpose of the study The cost effectiveness of trochanteric hip fractures in 1995 at Pitie-Salpetriere Hospital in Paris has been thoroughly analysed. The aim of this retrospective study was to identify the factors responsable for the variation in the treatment cost of those fractures. Material and methods Cost, Hospital stay, functional status, ASA score, mental status and surgical treatment were analysed in 74 patients aged over 60 years old. Results The mean cost per patient was 23901 FF divided as follows: 8,5 per cent for preoperative care, 40,5 per cent for surgical procedures, 51 per cent for post-operative care. The mean hospital stay was 18 days. The cost of hospital personel (44 per cent) and medical materiel (26 per cent) were the two main sources of hospital expenses beside medical investigations (11 per cent), hostelry (8 per cent), blood transfusion (6 per cent) and drugs (5 per cent). Discussion The duration of hospital stay was the only factor that affected statistically the mean cost per patient. Furthermore, factors related to the patient as age, sex, place of residence prior to admission, functional status, ASA score, mental status, had no influence on cost variation. Conclusion Therefore, the best way to reduce the cost of trochanteric fractures treatment is to develop convalescence structures to avoid a lengthy and costly hospital stay and to minimize the abuse utilization of medical materials.