The relationship between alcohol use prior to suicide was explored among American Indian decedents in New Mexico for the years 1980 through 1998. The suicide data were collected from New Mexico Vital Statistics and toxicology reports from the New Mexico Office of the Medical Investigator and matched on a case-by-case basis. Detailed analyses were undertaken for all cases of resident New Mexico Indians from the Navajo, Pueblo, and Apache cultures. Alcohol was detected in 69% of all suicides of American Indians with some variance by major tribal cultural groups (range = 62.1% to 84.4%). This is higher than in suicides among the overall New Mexico population (44.3%). The mean blood alcohol concentration (BAC) of the drinking Indian decedents at suicide was 0.198 (+/- SD of .088). Mean BACs were high for both males (0.199) and females (0.180) who had been drinking. Over 90% of the Indian decedents who had been drinking had BACs greater than the legal intoxication level of 0.08. The Navajo had the lowest percentage of cases that were alcohol involved, and their mean BAC was lower than the other two cultural groups. Alcohol use for completed suicides also varied somewhat by age, sex, method of suicide, and place of occurrence, but very little by whether the decedent was an on or off reservation resident. Analyses indicated that alcohol use prior to suicide was significantly more associated with male suicides than for females, and it was negatively correlated for those who died by overdose and also those using other drugs at suicide. Otherwise, alcohol use did not significantly differentiate American Indian suicides by age, use of firearms, hanging, use of other methods, or residence, for the presence of alcohol was a factor very commonly associated with all of these variables. Heavy alcohol consumption is, therefore, an important factor in over two thirds of all completed suicides among the Indians of New Mexico.