A case-control study on the relationship between alcohol dehydrogenase-2 (ADH2), aldehyde dehydrogenase-2 (ALDH2) and male probable alcohol use disorders (AUD) was performed in Khon Kaen, north-east Thailand. One hundred and fifty-three paired cases (probable AUD) and controls (non-probable AUD) were sampled from villagers aged 18-65 years using the modified Michigan Alcoholism Screening Test - Thai version, controls being matched for gender, age (+/- 4 years) and village. All of the cases and 86.9% of the controls were current drinkers. The percentage of ADH2*1/1 among cases was 47.1%, being significantly larger than the 29.4% among controls, and yielding a univariate odds ratio (OR) of 2.421* (95% confidence interval (CI) = 1.419-4.132) for developing probable AUD. The ALDH2*1/1 proportion among cases, 92.8%, was comparable to the 92.2% among controls, yielding a univariate OR of 1.100 (95%CI = 0.757-1.599). Multivariate analysis based on a conditional logistic regression model and a hierarchically well-formulated model strategy revealed that: (i) the OR of developing probable AUD due to 1 g increment of daily ethanol drinking was 1.110* among farmers (95%CI = 1.054-1.170); (ii) OR due to 1 g increment of daily ethanol drinking was 1.329* among non-farmers (95%CI = 1.109-1.593); (iii) OR due to either ADH2*1/1 or ALDH2*1/1 was insignificant; and (iv) the daily amount of smoking is independently associated with probable AUD. The present findings suggest that one of the genetic factors that may be related to probable AUD among Thai males living in the north-east is the ADH2 gene.