The purpose of this research is to document and explain ethnic variation in health among Latino adults in the United States. Results of analyses of data pooled from the 1997-2001 National Health Interview surveys reveal that health patterns are clearly different among Latino ethnic groups. Mexicans have health advantages, whereas Puerto Ricans experience health disparities. Cubans and Dominicans reveal a mix of health disparities and advantages, depending on the health outcome. The effects of social determinants of health are also contingent upon ethnicity. For example, worse health is associated with higher levels of socioeconomic status (SES) and acculturation among Mexicans, but with lower levels of SES and acculturation among Latinos whose origins are from Caribbean islands. We conclude that racial/ethnic comparative health research should avoid pan-ethnic groupings, and explicitly acknowledge ethnic group distinctiveness.