BACKGROUND: There is very limited literature on alcohol use among the elderly and little is known about the impact it has on family and caregivers, especially in low and middle income countries. AIM: To estimate the independent effect of heavy alcohol use among the elderly on the psychological health of their co-residents. METHODS: This is a secondary analysis using data from the comprehensive cross-sectional survey of the 10/66 dementia research group population-based research programme in the Dominican Republic. The characteristics of the elderly participants as well as the co-residents were described. The independent association of heavy drinking among the participants with psychological morbidity in their co-residents was estimated. Different models were generated to rule out potential mediating effects of disability and behavioural symptoms. RESULTS: Prevalence of heavy alcohol use in the elderly in Dominican Republic was 10.6%. There was a statistically significant independent effect of heavy alcohol use by the elderly on their co-residents mental health (PR=1.47; 95% CI 1.07-2.01) which was not accounted by disability (Sobel-Goodman test, p=0.15). Severity of psychological and behavioural symptoms partially (29.1% of the total effect) explained this association (Sobel-Goodman mediation test, p=0.006). CONCLUSIONS: Health services for the elderly in low and middle income countries will have to be configured around detection of alcohol problems among the elderly as well as offering appropriate support to their co-residents.