The satellite cell population in skeletal muscles of ten normal subjects aged 7 to 73 years was quantitated by electron microscopy. In all 1,414 nuclei were assessed. Satellite cell nuclei comprised 4% (standard deviation 2%) of all nuclei within the fibre basal lamina. The lowest incidence (0.6%) was found in a 73-year-old man. The study confirms, that satellite cells are regularly present in human skeletal muscle.