A positive secular trend for stature and weight is evident in rural Aymara-speaking Indians of the Parinacota Province (>3,000 m) in the northern Chilean Andes. The study is based on two cross-sectional growth surveys carried out in 1972 and 1987. In the survey of 1972, which was undertaken by other authors, a sample of 190 individuals was considered. The 1987 survey, performed by the present author, comprises a sample of 170 Indians. Both children and adults of each sex, ages 6-29 years, are included. Secular comparisons of age-grouped means indicate a secular increase in stature and weight in Aymara children, adolescents, and adults in the Parinacota Province between 1972 and 1987. The Aymara tend to be taller and heavier in 1987. The estimated secular increase for stature is 2.1 cm/decade for males and 1.8 cm/decade for females. For weight, the increase is 2.3 kg/decade for males and 1.5 kg/decade for females. In all cases, growth gains tend to be greater in males than in females. The body mass index also increases slightly. The secular changes in stature and weight are statistically significant in both sexes. From additional nutritional data on the Aymara samples compared, it is concluded that the observed secular increases might primarily reflect improved food supply over the past two decades. Am. J. Hum. Biol. 10:607-617, 1998. © 1998 Wiley-Liss, Inc.