Lower limb length discrepancy and angular deformities in children are a serious problem that commonly faces orthopaedic surgeons. Epiphysiodesis is a simple procedure with short learning curve and few complications. Timing of epiphysiodesis is a crucial point in planning the treatment. Arithmetic method, straight line graph, and multiplier method are among the most commonly used methods to predict the discrepancy at maturity and to define the proper time for epiphysiodesis.