The aim of this study was to investigate the association between contextual and individual demographic characteristics and alcohol consumption and smoking in southwestern China and southern Thailand. In 2000, a cross-sectional study was carried out in southern Thailand on 703 subjects > or = 45 years old, and in 2005 in southwestern China on 6,006 subjects. Each participant was interviewed by trained interviewers using a standard questionnaire. Information regarding demographic characteristics, alcohol drinking and smoking was obtained. Multilevel logistic regression was used to model variation in the prevalence of alcohol consumption and tobacco smoking. The findings in both countries indicate that age was negatively associated with the probability of consuming alcohol and males were more likely to consume alcohol and tobacco than females. Chinese communities with a lower level of education were more likely to smoke. Thai individuals with a higher educational level were less likely to smoke. Yi ethnicity was associated with a higher probability of drinking both at the contextual level and at the individual level in China. Non-Muslims were more likely to consume alcohol in Thailand. Future contextual and individual level interventions regarding alcohol drinking and smoking are needed in China, and further studies with larger sample sizes are needed in Thailand before conclusions can be drawn.