At least one-fourth of the over 45 aged population of the Zuni Indian reservation have diabetes. The true prevalence may be higher since an unknown number of Zunis had no blood sugar measurements during 1975-76 and therefore no opportunity for diagnosis. The high prevalence of diabetes among the Zunis has not been previously documented. It is similar to that found in the well-studied Pima Indians and much higher than that in a carefully examined large white population.