Second only to the Quechua-speaking peoples of the Andes, the Maya of southeastern Mexico and Guatemala constitute the “most impressive surviving American culture in the Western Hemisphere” (Vogt 1969a, 21). In Mexico the main division within the Maya falls between the highland population living in the state of Chiapas and the lowland group residing in the Yucatán Peninsula (Vogt 1969b). People of mixed Spanish and Indian ancestry, known locally as ladinos, make up most of the remaining population. Inspired by the well-known series of investigations of Indian and mestizo fertility in the Andean region, the present study seeks to describe within Mexico the fertility differences between the highland and lowland Maya and their ladino neighbors and, within the limits of the data, to account for the observed differentials.