The impact of child deaths on the nutrition status of surviving children in the Lake Titicaca basin in the Andes of southern Peru (altitude>3,800 m) is explored. Survey data on obstetric history and social variables were collected in a random sample of 86 households in two Aymara and three Quechua Amerindian peasant communities. Independently of social factors, deaths among older siblings under five years old were associated with improved nutrition stature in children under four. Improved head circumference for age in boys was associated with the death of an older sister. The findings point to a new hypothesis concerning nutrition status in this population: mortality in children under five can be related to improved nutrition status (as evidenced by head circumference and height) in surviving siblings under four.