OBJECTIVE To study retinal atrophy in idiopathic central serous chorioretinopathy (ICSC). METHODS Observational case series. METHODS Twenty-four eyes in 23 consecutive patients aged 33 to 67 years and 50 eyes in 25 healthy volunteers aged 24 to 70 years were studied. Observational procedures included: biomicroscopy, fundus photography, fluorescein angiography, optical coherence tomography, photocoagulation. Retinal thickness after resolution of detachment, definite attenuation being defined as foveal thickness less than the mean -2 SD in healthy volunteers; duration of symptoms; best-corrected visual acuity (BCVA). RESULTS Definite retinal attenuation, retinal thickness ranging from 51% to 74% of normal, was found in nine eyes of nine patients with idiopathic central serous chorioretinopathy (ICSC). Their duration of symptoms was longer (P =.0014) and their BCVA was lower (P =.015) than eyes in patients with normal-range foveal thickness who, nevertheless, had thinner foveae than healthy subjects (P =.10). The most severe reduction of foveal thickness, to half the normal (three eyes of three patients), was associated with BCVA 0.5 or less, multifocal retinal pigment epithelial abnormalities, and more than 10 years' duration of symptoms. Retinal attenuation was seen only after a duration of symptoms of more than 4 months, being most pronounced in the photoreceptor layer, particularly in the fovea. CONCLUSIONS Foveal attenuation in ICSC is associated with more than 4 months' duration of symptoms and persistent BCVA reduction despite resolution of the serous detachment. We found no other likely cause of atrophy than the prolonged absence of contact between photoreceptors and retinal pigment epithelial cells.