A system for custom fitting athletic shoes to an individual wearer includes a foot measurement device, an adjustable footform and an infrared activation chamber. Shoes of a single width for each length size have at least a portion of the upper made of heat malleable material to be custom fitted for width. Foot measurement data is used to calculate length size, width size and a number of custom adjustment factors. After the length size is calculated, the appropriately sized shoe and last are assembled together and subject to infrared radiation until the heat malleable material becomes plastic. Adjustments are then made to the last in accordance with the adjustment factors to provide custom width sizing. After further heat treatment to set the shoe upper and cooling, the shoe is complete. In this manner, if used in a retail setting, shoes are custom fitted to the wearer in a matter of minutes.