Selection of optimal machining parameters is a difficult process due to the large number of variables and their complex interdependencies. In this study, a genetic algorithm-based method is presented to determine the optimal machining parameters for machining pockets using multi-pass end milling operations. The number of passes, axial and radial depths of cut, and feed rate are determined to minimize a cost function that is based on the cutting force. Results are presented for two different tool paths using a mechanistic model for predicting the cutting force.