Few US studies have assessed racial disparities in viral respiratory hospitalizations among children. This study enrolled black and white children under 5 years of age who were hospitalized for acute respiratory illness (ARI) in 3 US counties during October-May 2002-2009. Population-based rates of hospitalization were calculated by race for ARI and laboratory-confirmed influenza and respiratory syncytial virus (RSV), using US Census denominators. Relative rates of hospitalization between racial groups were estimated. Of 1,415 hospitalized black children and 1,824 hospitalized white children with ARI enrolled in the study, 108 (8%) black children and 111 (6%) white children had influenza and 230 (19%) black children and 441 (29%) white children had RSV. Hospitalization rates were higher among black children than among white children for ARI (relative rate (RR) = 1.7, 95% confidence interval (CI): 1.6, 1.8) and influenza (RR = 2.1, 95% CI: 1.6, 2.9). For RSV, rates were similar among black and white children under age 12 months but higher for black children aged 12 months or more (for ages 12-23 months, RR = 1.7, 95% CI: 1.1, 2.5; for ages 24-59 months, RR = 2.2, 95% CI: 1.3, 3.6). Black children versus white children were significantly more likely to have public insurance or no insurance (85% vs. 43%) and a history of asthma/wheezing (28% vs. 18%) but not more severe illness. The observed racial disparities require further study.