The retinal function of the delayed amelanotic (DAM) chicken that has progressive retinal degeneration, was investigated electroretinographically (ERG). Subjects showing a gradation of abnormalities of retinal morphology and impairment of visual behaviors were tested. Dark-adapted a-, b-, and c-wave responses to full-field stimuli were studied. In general, the more severe the anatomical abnormalities, the greater the compromise of sensitivity and amplitude of ERG responses. The DAM disease appears to affect c-waves more than a-waves, and a-waves more than b-waves. Dark-adapted responses are affected more than light-adapted responses. In DAM's with moderately to severely impaired visual behaviors, ERG studies should permit analysis of the distal retinal pathophysiology caused by this disease.