The proximal femur is a common area for primary and also metastatic bone tumors. The objective of this study was to assess the long-term functional and oncological outcomes of patients with malignant primary or secondary tumors of the proximal femur, who underwent proximal femoral resection then reconstruction using bipolar modular tumor prosthesis. Sixty patients with proximal femoral malignant tumors underwent resection and bipolar modular prosthesis between 2000 and 2016, were retrospectively reviewed. Based on diagnosis and presence or absence of pathological fracture, patients were divided into groups. The functional outcome of the patients was evaluated using the Musculoskeletal Tumor Society (MSTS) functional scoring system for the lower extremities. The mean age was 38 (9-80) years at the time of primary surgery. Pathological fracture was the presentation in 28 patients. The study included 44 patients with primary bone tumor and 16 patients with a secondary bone tumor. The mean MSTS functional score of the patients was 24.3 (range, 18-30) points with no significant difference in patients with primary or secondary tumors. The rate of complications in the present series was 45%. The most frequent complication was an infection in 10 patients (16.7%), followed by aseptic loosening in 7 patients (11.7%). Local recurrence of primary bone tumors occurred in three out of 44 patients (6.8%). Modular bipolar tumor prosthesis has a good long-term functional result in both primary and secondary tumors of the proximal femur, with no significant effect of age, presence or absence of pathological fracture or femoral resection length on the functional outcome. It was found that the only statistically significant variable regarding the risk of infection is previous surgeries. Level IV, retrospective case series.