Four generations in a family were affected by butterfly-shaped macular dystrophy. Affected members ranged in age from 8 to 77 years. In addition to the primary features of autosomal dominant inheritance, bilateral symmetrical pigmented macular lesion, and a low electrooculographic light peak-dark trough ratio, we discovered additional progressive changes: peripapillary and parafoveal chorioretinal atrophy, enlarged blind spots, and paracentral scotomas with diminished visual acuity late. Because of the progressive change in the ophthalmologic appearance of the fundus, the diagnosis could easily be overlooked in advanced cases.