Disclosed is a modular femoral sizing guide which facilitates the selection and rotational orientation of a femoral prosthetic for a resected femur. The femoral sizing guide has a base which is coupled to the resected femur. An extension portion which is configured to have a pair of feet which are coupled to the posterior surface of the resected femur is rotatably coupled to the base portion. A superstructure having a pair of drilling guides and a stylus is slidably coupled to the base.