Assessed social integration (existence or quantity of relationships) and social (specifically, emotional) support in Mexican Americans (MAs) and non-Hispanic whites (NHWs). Ethnic differences were seen as arising from (a) demographic differences between ethnic groups that account for ethnic differences; (b) demographic attributes that have different associations with social resources for each ethnic group; (c) ethnic differences independent of these explanations. Study participants were 538 U.S.-born MA, 706 Mexico-born MA, and 1,149 NHW randomly selected community residents. Immigrants were more often married, and MAs and immigrants reported fewer friends and less emotional support, regardless of demographic attributes. Ethnic differences in demographic attributes accounted for MAs' and immigrants' smaller kin networks. Ethnic differences in demographic correlates of working accounted for MAs' lower employment rates.