This is the first study of alcohol-related problems among a Latin American indigenous population using the Alcohol Use Disorders Identification Test (AUDIT). A randomly selected community sample consisting of 3% of the adult population of the tribe completed oral interviews (n = 105 adults, completion rate 86%). The majority of both men (98%) and women (53%) had drunk alcohol at some time in their lives, with 94 and 26% respectively having consumed alcohol within the past 12 months. Using a cut-off score of 8 for the AUDIT, 86.5% of all men and 7.5% of all women were found to be problem drinkers. Focus group discussions revealed that traditional patterns of binge drinking of corn liquor had gradually been replaced by consumption of commercial beer and rum at more frequent intervals and with more negative social consequences. This male population demonstrates one of the highest prevalence rates for problem drinking reported in the world literature. Both the magnitude of problems detected and participants' concerns about them suggest that broad-scale interventions are warranted at the community level.