Anthropometric data were obtained from 209 Mexican-American migrant children, aged 0 to 7 yr, in the Sacramento Valley of California. Hematocrit was measured for 170 children. Only 13 children (7.6%) had hematocrits below acceptable levels. Weight-for-age, height-for-age, and weight-for-height growth percentiles approximated the National Center for Health Statistics standards. Only 15% of the children were at or below the 10th percentile of height-for-age, and only 7% were above the 95th percentile of weight-for-height, in contrast to earlier studies of Mexican-American children. The mean percentile of weight-for-height increased significantly with age, while height-for-age decreased. The rate of growth in weight and height accelerated during their summer residence in the US, indicating that the adequate growth status of these children may be related to improved conditions for growth while in the US.