Contamination of the external surface of anticancer drug vials supplied to hospital pharmacies has been recognized as a potential health hazard. The aim of this study was to investigate the levels of contamination on the exterior surface of vials containing platinum anticancer drugs in Japan. Platinum contamination on the exterior surface of vials containing cisplatin or carboplatin was examined using products commercially available in Japan. Cisplatin vials from 42 batches (2 drug contents, 10 products and 5 manufacturers) and carboplatin vials from 28 batches (3 drug contents, 7 products and 3 manufacturers) were used. Five vials were randomly sampled from each batch. Exterior contamination levels of 0.070-144 ng/vial as cisplatin and 0.21-1630 ng/vial as carboplatin were detected. Significant differences in the levels of contamination among the batch numbers were observed in 6 of 10 cisplatin products and 6 of 7 carboplatin products. Significant differences in the levels of contamination were observed in 3 cisplatin products with different contents of drug within the vials and 1 carboplatin product with different contents of drug within the vials. Significant differences in the contamination levels among the cisplatin manufacturers but not carboplatin manufacturers were observed. The degree of contamination of the carboplatin products was significantly higher than that of the cisplatin products. In conclusion, external contamination was confirmed in all cisplatin and carboplatin vials tested. The degree of contamination was different among different batch numbers, drug contents, manufacturers, and platinum anticancer drug.