To investigate the association between the potentially functional polymorphisms in IL12A and IL12B, HBV infection and risk of hepatocellular carcinoma in a Chinese population, we genotyped three polymorphisms, rs568408 (3'UTR G>A), rs2243115 (5'UTR T>G) in IL12A and rs3212227 (3'UTR A>C) in IL12B in a case-control study of 869 hepatocellular carcinoma (HCC) cases and 891 cancer-free controls.