Background: Fractures of the proximal extremity of the femur are among the commonest traumatic injuries nowadays, not only because of their high incidence in the elderly population but also because of the accompanying morbidity and mortality. A well-documented report has suggested that body mass index (BMI) is a significant prognostic factor for hip fractures. Fractures of the proximal femur may be associated with low BMI, which is considered to be a risk factor. Objective: To evaluate the effect of BMI on the outcome and complications of traumatic proximal femoral fractures in patients who were treated at Mansoura University Emergency Hospital. Patient and method: This was prospective observational non-controlled clinical study was carried out on 134 patients with traumatic proximal femoral fractures selected from Mansoura University Emergency Hospital trauma patients from November 2018 to November 2019. Results: This study demonstrated that the mean duration of hospital and ICU stay were (11.18 ± 8.23) and (0.49 ± 1.26) respectively. The percentage of overall morality was (7.5), (1.5) of which occurred in the first day while the remaining cases occurred in the first month (6%). All demographic data and medical history were comparable among the studied cases except for height, weight and BMI indicating that BMI was the only different factors among cases. Incidence of postoperative complications was not affected by altered BMI. Duration of hospital and ICU admission wasn't affected by alteration in BMI but significantly affected the mortality in the first day. Conclusion: The incidence of proximal femur fracture was higher in cases with higher BMI.