The purpose of this study was to compare architectural characteristics of leg muscles of basketball players and rugby players. Increase in pennation angle allows for a greater number of fibers to be present within a given cross-sectional area and thus is often associated with increased strength. Differences in maximal shortening velocity among muscles are associated with differences in muscle fascicle length. Skeletal muscle architectural characteristics were studied in 8 elite male basketball players, 11 elite male rugby players, and 13 untrained male controls. Pennation angle of the lateral gastrocnemius and soleus muscles was significantly greater in rugby players than in either basketball players or controls. Fascicle length of the lateral gastrocnemius muscle was significantly greater in rugby players than controls. Greater pennation angle and similar fascicle length observed in medial·lateral gastrocnemius of rugby players would appear to favor increased strength.