In anesthetized albino or nonalbino rabbits, a 3-8 mg/kg i.v. injection of the antipsychotic chlorpromazine did not affect a-wave amplitude of the electroretinogram (ERG). Immediately after the injection of the drug, b-wave amplitude increased. The maximum increase occurred between 35-50 min and the recovery time varied between 5-8 h. Initial changes in the b-wave amplitude to some extent were affected by systemic changes in the blood pressure. The b-wave amplitude remained high for a long time after the blood pressure reached preinjection value, indicating a local effect of the drug. There was no change in a- or b-wave latencies. In vitro a large quantity of chlorpromazine can be localized in the melanin granules from pigmented rabbit retina, but in vivo the ERG b-wave changes caused by the small i.v. dose of the drug were similar in both albino and nonalbino rabbits.