The determination of years of potential life lost (YPLL) can aid in monitoring changes in premature mortality among various population groups. While premature mortality has been shown to differ among blacks and whites, patterns of YPLL have not been well established among other racial groups. The Seneca Nation of Indians (SNI) is a Native American group residing primarily in western New York State (NYS). A review of SNI necrology records revealed that 55 percent (510 of 924) of the deaths between 1955 and 1984 occurred before 65 years of age. The proportion of premature deaths among males exceeded the proportion in females. SNI males demonstrated an increased risk of premature death (odds ratio = 1.43) relative to SNI females. Both the percentage of premature deaths and the number of YPLL per death were greater among SNI members compared with NYS residents. Almost one-half of all YPLL among the SNI were attributable to accidents and injuries. Heart disease, digestive diseases, and malignant neoplasms also represented important contributors to YPLL for both SNI males and females. This investigation identifies important causes of premature death among a Native American population and underscores the preventable nature of premature loss of life.