Acute posterior multifocal placoid pigment epitheliopathy is a non-granulomatous chorioretinitis of uncertain origin that occurs in healthy young adults. The prevailing opinion is that the disease has a good long-term prognosis for visual acuity because it is self-limiting and chorioretinal scars do not enlarge with time. A middle-aged adult male who had acute posterior multifocal placoid pigment epitheliopathy in one eye has been followed for 22 years. After apparent clinical healing of the placoid epithelial lesions, widespread severe choroidal atrophy with visual loss occurred and progressed over years without interruption. To our knowledge this is the second report of progressive deterioration of a supposedly self-limiting chorioretinal disease.