Carboplatin is a well-established chemotherapeutic agent used to treat a variety of pediatric malignancies. Platinum analogues such as cisplatin are known to be ototoxic, but little is known regarding the ototoxicity of carboplatin. We performed a single institution retrospective chart review of pediatric oncology patients who received platinum-containing regimens from 1993 to 2002. Ninety-nine patients with sufficient medical and audiologic data were identified. Significant hearing loss was defined as a Brock grade 1 or higher. The incidence was compared among 3 treatment groups (carboplatin only, carboplatin and cisplatin, and cisplatin only). Significant hearing loss in patients receiving carboplatin only was rare, observed in only 1/25 (4%) of patients. In contrast, 19/27 (70%) of patients receiving carboplatin and cisplatin possessed significant hearing loss, as did 27/47 (57%) of those patients receiving cisplatin only P<0.001. The difference in hearing loss could not be explained by different cumulative exposures of the platinum agents. Carboplatin, when used without cisplatin, is rarely associated with severe hearing loss, even at high cumulative doses.