This investigation is aimed at recording the conditions of life and of reproduction of the population of the rural districts of the Province of Chubut, in South Patagonia. These districts, where in 1991 more than 50% of the population lived in towns of less than 2000 inhabitants, have an important indigenous component of the Tehuelche and Mapuche ethnic groups, with particular behaviour affecting growth and development variables, patterns of food consumption, morbi-mortality, etc. in socio-economic and ecological context of considerable adversity. The climate is by low precipitation, less than 120 to 180 mm, producing an arid steppe environment. The annual average temperature is between 7°C and 9°C. The summers are short and temperate, in contrast to very cold and long winters with frequent snowstorms. The temperature normally reaches extremes that go from −10° to −33°C in winter. Seven anthropometric variables were measured on 678 children from 4 to 14 years of age to test for altered patterns of growth. Compared with another Argentinean population it was found that there were differences in standing and sitting height, significant in some groups of edge greater for national standards. Head circumference, weight, triceps and subescapular skinfolds showed the opposite relationship. We estimate that in this population there would be selected phenotypes adapted to adverse conditions.