This prospective study was done to evaluate the result of interlocking intramedullary nailing in fracture shaft of the femur under the Department of Orthopaedic Surgery in Mymensingh Medical College Hospital during the period of January 2007 to December 2008. In this study total 66 patients were purposively selected for interlocking nailing initially but 6 patients did not report in subsequent follow up. So, the result of the study was based on 60 patients. There were 38 males and 22 females with the age range of 18 to 70 years, with an average age of 34 years. Motor vehicle accident was the most common cause of the fracture shaft of the femur (60%) and the second most common cause was fall from height (20%). Right sided involvement was more (66.67%). Majority of the patients had fracture lower third of the femur (70%). Among the patients farmer was the most common (33.33%) group and the next was housewife. The mean union time was 17 weeks with the range of 14 to 30 weeks. Postoperative complications were found, such as infection (3.33%) and nonunion (1.66%). The functional outcome of this study was evaluated by Klemm & Borner criteria. Excellent functional outcome was found in 80%, good in 15% and fair in 5%.