Anthropometric data were obtained from children and adults of 71 migrant and 69 nonmigrant low‐income first‐generation Mexican‐American families. Nonmigrant children (1–11 years) were very close to U.S. standards in weight‐for‐age, height‐for‐age, weight‐for‐height and triceps skinfold, while migrant children were shorter and fatter. Adolescents (12–19 years) in both groups were shorter than U.S. standards, probably due to an increasing effect of shorter leg‐length at older ages. Among younger children, the proportion of life spent in Mexico prior to moving to the U.S. was not related to present growth status, but adolescents who had spent more of their lives in Mexico were shorter. Growth status of all children was related to maternal weight and height and family income, among other factors. Among adults, 55 percent of women and 43 percent of men exceeded 120 percent of “ideal” weight. Obesity increased with age, but was unrelated to length of residence in the U.S.