A mother and daughter having ichthyosis follicularis with alopecia and photophobia (IFAP) are reported, with histopathological and electron microscopic findings. We have followed the clinical course of the mother for 26 years since she was 5 years old, and the daughter since birth. They have had almost all the classical and some of the minor symptoms of IFAP, including severe photophobia, extensive non-inflammatory follicular hyperkeratosis, generalized non-scarring alopecia, hyperkeratosis of the extensor aspect of the four extremities, nail deformity and recurrent cheilitis. In addition, their facial appearance greatly resembles that of previously reported patients. A consistent feature in the mother was florid keratotic inflammatory eruptions on the genital region during each of her pregnancies, which rapidly improved after the delivery. Skin biopsy of the genital lesion showed marked acanthosis with dyskeratosis and spongiotic changes. The electron microscopic examination of diseased skin showed damaged desmosomes with spongiosis. No obvious changes were found in normal appearing skin.