Objectives: In non-operative methods, hip spica casting is a gold standard for children under six years of age because of excellent bone union and remodeling qualities. The study was conducted to determine the frequency of limb shortening in femur shaft fractures in children treated by hip spica casting. Study Design: Descriptive cross sectional study. Setting: Orthopedics Department of Combined Military Hospital, Rawalakot, Pakistan. Period: One year from July, 2016 to June, 2017. Material and Methods: After approval of the study from institution’s ethical committee, all patients fulfilling the inclusion criteria were admitted through emergency or outpatient department for hip spica casting. It was descriptive cross sectional study and sampling was done by non-probability convenience sampling in 107 femur fracture patients treated by hip spica casting. Diagnosis of the fracture was based upon history of trauma with break in the continuity of shaft as seen by X-ray. Informed consent was obtained from parents/guardian to be included in the study. Results: The mean age was 5(± 2.04) years. Sixty eight percent patients were male and 32% were female. Sixty three percent patients had proximal femoral shaft fracture, 32% had middle femoral shaft fracture and 4% patients had distal femoral shaft fracture. The shortening of limb length was found in14% of patients. Conclusion: In closed femoral shaft fractures, hip spica casting is a safe treatment in children. It has a low risk of complications. We recommend its use except for open fractures, multiple fractures, or fractures in older children.