Background and aims: Osteoporosis has been traditionally considered as a disease in women. However, it is now known that this condition is also important in men. It is a multifactor condition whose main independent risk factor to suffer fractures, in general, and those of the hip, specifically, is bone mass. Nonetheless, there are other independent risk factors of importance. This study has aimed to study if men and women suffer hip fractures with the same bone mass and if they have the same risk factors associated to this condition. Patients and methods: We studied 105 patients with non-traumatic hip fracture and 68 healthy controls. The different risk factors were analyzed, including clinical data, lifestyle, analytic data, data related to bone metabolism and sex hormones as well as a complete bone evaluation. Results and conclusions: Hip bone mass density (BMD) values are the main risk factor for osteoporotic fractures in both genders. These values are comparable when expressed in terms of volumetric density. In women, risk factors that determine the appearance of fractures are previous non-traumatic fractures when they are older than 50 years, total hip BMD, serum calcium levels and thiazide intake while in men only total hip BMD reaches statistical significance. (C) 2010 Elsevier Espana, S.L. All rights reserved.