Since 1982, the Air Force Health Study has continued to assess the mortality for veterans of Operation Ranch Hand, the unit responsible for aerially spraying herbicides in Vietnam. The mortality for 1,262 Ranch Hand veterans to December 31, 1999 was contrasted with that for 19,078 comparison veterans. The relative risk (RR) for all-cause death was borderline significantly increased (RR, 1.15; 95% confidence interval, 1.0-1.3; p = 0.06). The risk of death caused by cancer was not increased (RR = 1.0), but the risk of death caused by circulatory system diseases was significantly increased among enlisted ground crew workers (RR = 1.7; 95% confidence interval, 1.2-2.4; p = 0.001). Results for Ranch Hand all-cause death differed from previous reports, with the RR now exceeding 1.0. The risk of death attributable to circulatory system diseases continues to be increased, especially for enlisted ground crew, a subgroup with relatively high skin exposure to herbicides.