We studied the localization of dystrophin in normal human fetal muscle by immunohistochemistry. Our results show the appearance of dystrophin at week 11 and a progressive organization of the protein along membrane in the following weeks of gestation. At week 22 almost all fibers show a clear membrane immunostaining. Concomitant analysis of muscle fiber-type composition reveals no correlation between progressive appearance of dystrophin and muscle fiber-type differentiation. Our findings suggest that synthesis and localization of dystrophin in developing human skeletal muscle is time-related and probably independent of neuronal influences.