Three young children showed a similar fundus appearance of sharply defined, yellowish-white, patchy or geographic atrophy of the retina and choroid and visible large choroidal vessels in almost the entire fundus. Fluorescein angiography disclosed atrophy of the retinal pigment epithelium and loss of choriocapillaris. Their visual functions and electrophysiologic findings were also similar. Family A was diagnosed as having diffuse choriocapillaris atrophy with autosomal dominant inheritance; family B, choroideremia with X-linked recessive heredity; and family C, gyrate atrophy of the choroid and retina with hyperornithinemia and autosomal recessive transmission. It became evident that diffuse choriocapillaris atrophy, choroideremia, and gyrate atrophy sometimes show a similar fundus appearance. Fluorescein angiography, serum ornithine levels, and family history were particularly helpful to differentiate these diffuse choroidal atrophies.