PURPOSE--To evaluate arterial blood pressure (BP), variations that occur with age, influence of new habits, in indians of a Xavante tribe, located in the state of Mato Grosso, Brazil. METHODS--The evaluation procedures took place in 9/75 and 10/90. Fifty Xavante were examined in 1975. Thirty-five of them were men and 15 women. The mean age of the men was 45 and of the women, 31. In 1990, only 46 of those indians were re-examined (two were not located and two had already died of cancer and pneumonia), and evaluated with regard to arterial BP, food ingestion, physical activities, obesity, tobacco, alcoholic beverage consumption and social organization. RESULTS--In both occasions we did not find individuals with hypertension. The highest BP observed was of 140 x 90 in a 70-year-old indian. His result is consistent with what had been noted in 1975. Among the women, the highest level was of 130 x 60 in a 55-year-old female indian. The women maintained a lower level of BP as compared to the men of any age group. The average blood pressure showed a discrete increase going from 79.2 to 83.8 mmHg in the men and from 75.7 to 77.0 mmHg in the women. In this tribe we observed the habit of smoking in 30 per cent of the individuals. Alcoholic beverage consumption is rare, physical activities remained constant and obesity is absent. As for the eating habits, with the decrease of hunting grounds, the indians acquired a more rural behavior with regular use of rice and beans. Salt is practically not added to the food. Competitiveness is not an acquired trait to that culture. CONCLUSION--In isolated populations that maintain their cultural traits and basic life styles, the occurrence of arterial hypertension is very rare and the increase in BP with age is modest and significant only for systolic