OBJECTIVE: To analyze the prevalence of acute asymptomatic group A and C rotavirus (RV-A and RV-C) infection in neonates with cholestasis. STUDY DESIGN: Participants were infants <180 days of age with cholestasis (serum direct or conjugated bilirubin >20% of total and >/=2 mg/dL) enrolled in the Childhood Liver Disease Research and Education Network during RV season (December-May). Forty infants with biliary atresia (BA), age 62 +/- 29 days (range, 4.7-13 weeks) and 38 infants with cholestasis, age 67 +/- 44 days (range, 3-15.8 weeks) were enrolled. RESULTS: At enrollment, RV-A IgM positivity rates did not differ between infants with BA (10%) vs those without (18%) (P = .349). RV-C IgM was positive in 0% of infants with BA vs 3% in those without BA (P = .49). RV-A IgG was lower in infants with BA: 51 +/- 39 vs 56 +/- 44 enzyme-linked immunoassay unit, P = .045 but this difference may lack biological relevance as maternal RV-A IgG titers were similar between groups. Infant RV-A IgM titers at 2-6 months follow-up increased markedly vs at presentation in both infants with BA (50 +/- 30 vs 9 +/- 9) and those without (43 +/- 18 vs 16 +/- 20 enzyme-linked immunoassay unit) (P < .0001), without differences between groups. CONCLUSIONS: RV-A infection in the first 6 months of life is common in infants with cholestasis of any cause. RV-A could have different pathogenetic effects by initiating different hepatic immune responses in infants with vs without BA or could lack pathogenetic significance.