Necropsies were obtained from 5 muscles from 5 young women.The muscles subjected to morphometrical analysis were the deltoid, brachial biceps, vastus lateralis, gastrocnemius and soleus. Results of measurements taken indicate significant differences in fibre sizes and fibre type composition in analogous muscles between individuals and between different muscles within individuals. Differences.were also encountered in muscle fibre size during rigor mortis for up to 48 h after death. Our results suggest that the fibre size variability between individuals determined from necropsy samples will contain a component of induced variation not found in muscle biopsies.