BACKGROUND: In the United States, Hispanics are less likely to undergo colorectal cancer (CRC) screening than non-Hispanic whites (whites). OBJECTIVE: To examine factors associated with disparities in CRC screening between whites and Hispanic national origin subgroups. DESIGN: Cross-sectional analysis of 1999-2005 Medical Expenditure Panel Survey data. PARTICIPANTS: Respondents aged >50 years self-identifying as non-Hispanic white (18,733) or Hispanic (3686)-the latter of Mexican (2779), Cuban (336), Puerto Rican (376), or Dominican (195) origin. MEASUREMENTS: Dependent variable: self-report of up to date CRC screening, defined as fecal occult blood testing within 2 years and/or lower endoscopy at any time. Independent variables: ethnicity/race, country of origin, interview language, socio-demographics, and access to care. RESULTS: Unadjusted CRC screening rates were highest in whites [mean (standard error), 55.9 (0.6) %], and lowest in Dominicans [28.5 (4.2) %]. After demographic adjustment, CRC screening was significantly lower for Mexicans [adjusted odds ratio (95% confidence interval), 0.46 (0.40, 0.53), p < 0.001)], Puerto Ricans [0.65 (0.47, 0.91), p = 0.01], and Dominicans [0.30 (0.19, 0.45), p < 0.001] versus whites. With further adjustment for language, socioeconomic factors, and access, Hispanic/white disparities were not significant, while among Hispanics, Cubans were more likely to be screened [1.57 (1.15, 2.14), p = 0.01]. CONCLUSIONS: Factors associated with CRC screening disparities between Hispanics and non-Hispanic whites appear similar among Hispanic sub-groups. However, the relative contribution of these factors to disparities varies by Hispanic national origin group, suggesting a need for differing approaches to increasing screening for each group.