Pregnant Sprague Dawley rats were exposed to adriamycin, an anthracycline antibiotic used in the treatment of neoplasms, and offspring were evaluated for renal functional competence using a variety of physiological techniques. Exposure consisted of 0, 1.0 or 1.5 mg/kg by intraperitoneal injection on either gestational days 7-10 or 10-12. Exposure during days 7-10 of gestation produced greater evidence of overt developmental toxicity than did exposure during days 10-12 of gestation. The reverse was true, however, for the effects of adriamycin on renal function, as the majority of effects on these measures (including decreased creatinine clearance, increased fractional excretion of water, decreased renal concentrating ability and decreased ability to excrete an acid load) were found in the high dose pups exposed during days 10-12 of gestation.