The clinical features of pigmented lens striae were studied biomicroscopically in seven patients. The lenses of three of these, obtained by cataract surgery, were examined by electron microscopy to determine the structure of the striae. We concluded that the striae are not formed by remnants of tunica vasculosa lentis, as earlier workers believed, but consist of fine fibrils of zonular bundles entrapping pigment granules of uveal origin.