We investigated the age-related change in the distribution of a molecular marker for neural stem and precursor cells, Musashi-1, in the olfactory epithelium of mice from 1 day up to 16 months of age using immunohistochemistry. We also compared the distribution pattern of Musashi-1 with that of growth-associated protein 43, the olfactory marker protein, and Notch-1. Musashi-1 was expressed in the globose basal cell layer and the lower part of the growth-associated protein 43-positive layer, with immunoreactivity decreasing with aging. Notch-1 was observed only in the early postnatal period. These findings are consistent with the fact that globose basal cells are proliferating olfactory precursor cells and that their ability to generate new neurons decreases with aging.