Pertrochanteric femur fractures are considered amongst the most commonly encountered fractures in the geriatric age group. We evaluated radiographic and functional outcomes of patients with unstable pertrochanteric fractures treated with the proximal femur nail antirotation (PFNA). Between March 2013 and December 2015, fifty patients (28 male and 22 females with a mean age of 72.8 years (range, 20–94)) with unstable pertrochanteric fractures (AO 31.A2 and 31.A3) were fixed with the PFNA at our institution, and they were retrospectively evaluated. Forty one patients were treated with short PFNA and nine with long PFNA. Operative time ranged between 30 and 150 (average 73.60) min, blood loss ranged between 50 and 250 (average 80) milliliter and hospital stay ranged between 3 and 18 (6.86) days. The mean follow-up period was 18 months (range, 11–31). At final follow-up, solid union of all fractures had been achieved without any implant-related complications, the mean Harris Hip Score (HHS) was 79.34 ± 9.10 points and the mean neck-shaft angle was 127.2° ± 5.07°. No significant differences were encountered between the functional and radiographic outcomes of the PFNA with regards to the AO fracture classification and the implant version. PFNA is a recommended option for the treatment of unstable pertrochanteric fractures owing to its easy insertion, reduced blood loss, stable fixation and satisfactory functional and radiological outcomes.