Hexachlorophene (HCP) in very large doses has a toxic effect on the retina of adult rats. The present study examined the sensitivity of the developing retina to smaller doses and its ability to recover from neurotoxic damage. Suckling rats were intoxicated with HCP added to the mothers' diet. The retinae of the pups were examined by light and electron microscopy for early and late effects. All dose levels above 100 ppm caused vacuolar degeneration of the outer segments of photoreceptor cells within 14 days of intoxication, followed by degeneration of the inner segments after 28 days. The cell bodies of photoreceptor cells and all other retinal layers remained normal. Suckling intoxicated with HCP (100 - 500 ppm) added to the mothers' diet for 28 days and then withdrawn, showed no recovery of the outer or inner segments o photoreceptors when examined up to 150 days later. In addition, extensive degeneration and loss of photoreceptor cell occurred after withdrawal of HCP and the degenerative process extended to involve the inner nuclear layer. The rate of appearance of pathological changes was proportional to the total amount of ingested HCP. This study showed that photoreceptor cells in newborn rats are highly sensitive to HCP. The retinal lesions were irreversibly an continued to progress by continued trans-synaptic degeneration after withdrawal of the toxic agents.