This article examines the incidence of various biomedical diseases among the Navajo Indians in New Mexico, Colorado, Utah & Arizona. Information on suicide is presented for all American Indians. It is noted that in 1967 the suicide rate among natives was 17 per 100,000 compared to 10.8 per 100,000 among non-Indians. Among the Indians, 83% of suicides were committed by males compared to 74% in the rest of the USA. A peak in suicides was noted between the ages of 15 & 20. (47 refs.)