To investigate a possible relationship between hepatitis C virus infection and cholestasis of pregnancy, we identified all cases of cholestasis of pregnancy (145/16,271) and hepatitis C virus infection (63/16,271) between January 1992 and December 1997. Serologic screening was performed universally. The rate of cholestasis of pregnancy was greater in women whose hepatitis C virus antibodies were positive rather than negative [15.9% (10/63) vs 0.8% (135/16,208), P < 0.001]. Among women with cholestasis of pregnancy, mean (standard deviation) gestational age at onset of symptoms and at delivery was significantly lower among women whose hepatitis C virus antibodies were positive compared with negative women: 28.9 (3.2) vs 34.3 (3.5) weeks, P < 0.001 and 36.3 (0.9) vs 37.0 (1.6) weeks, P = 0.03, respectively. These findings suggest that early occurrence of cholestasis of pregnancy may be an indication for serologic testing for hepatitis C virus.