This article examines segmented assimilation among foreign-born and U.S.-born Mexicans. Using the 2000 census, this article investigates how immigrants' length of residence in the United States and nativity affect the earnings and self-employment outcomes of low- and high-skilled Mexican men and women in the Southwest. Findings reveal that the earnings of low-skilled, foreign-born Mexicans decrease as immigrants reside in the United States longer and are generally lower among the U.S. born than the foreign born. In contrast, the earnings of high-skilled, foreign-born Mexicans increase as immigrants reside in the United States longer and are generally higher among U.S.-born Mexicans than foreign-born Mexicans. Moreover, self-employment participation decreases as immigrants reside in the United States longer and is lower among the U.S. born than the foreign born, regardless of skill. Since self-employment results in lower earnings, a decline in self-employment indicates economic progress. Furthermore, men are generally better off than women. Drawing from segmented assimilation theory, findings support the “downward assimilation” hypothesis among low-skilled Mexicans and the “Anglo-conformity” hypothesis among high-skilled Mexicans. Overall, this research provides evidence of intragroup differences in segmented assimilation among foreign-born and U.S.-born Mexicans in the Southwest.