Processes governing the ethnic identification of second and later generations of Mexican immigrant descendants are explored empirically using the Latino National Political Survey, 1989–1990. With multinomial logit regressions, I test hypotheses based on three contrasting perspectives, namely, that ethnic identification, or identification other than “American,” arises directly from: a) cultural continuity and a lower level of assimilation; b) an experience of ethnic competition; and c) both processes. The results from the LNPS support the view that both processes are at work. For example, consistent with the presence of an assimilation process, the chance of “Mexican” identification (as opposed to “American” identification) declines to half in the third generation and to one tenth in the fourth and later generations, relative to the chance in the second generation. Consistent with the presence of an ethnic competition process, (perceived) experience of discrimination doubles the respondents chance of “Mexican” identification. Also, a level rise in the darkness of skin color is associated with a 60 percent increase in the chance of Mexican identification.