Objective: To obtain estimates of the relationship between alcoholism and health-related quality of life (HRQL) in twin pairs discordant for alcohol dependence. Method: In 1995, 1,258 male-male twin pair members of the Vietnam Era Twin Registry (total Registry N = 7,375 pairs) were administered a modified Medical Outcomes Study 36 Item Short Form (SF-36) and the Diagnostic Interview Schedule (DIS) to obtain measures of HRQL and a DSM- III-R criteria lifetime diagnosis of alcohol dependence. Mean within pair differences on eight separate SF-36 subscales were calculated for 436 remitted (no alcohol symptoms in the past 5 years) alcohol-dependent discordant twin pairs and for 194 recent (at least one alcohol symptom in the past 5 years) alcohol-dependent discordant pairs before and after adjustment for covariates. Covariates included lifetime physical illness, lifetime psychiatric disorders, lifetime drug dependence, lifetime nicotine dependence, current marital status, current income and severity. Results: In the unadjusted analysis remitted alcoholic twins compared to their nonalcoholic co-twins reported significantly lower mean scores for six of eight SF-36 subscales. Recent alcoholic twins, compared to their nonalcoholic co-twins, reported significantly lower mean scores for all of the SF-36 subscales. However, after simultaneous adjustment for all covariates, no SF- 36 subscale mean, except 'vitality' among recent alcoholic twins, was significantly different between alcoholic twins and their nonalcoholic co- twins. Conclusions: Differences in HRQL between alcoholic and nonalcoholic co-twins is due to covariation from physical and psychiatric problems, drug and nicotine dependence, marital status, income and severity.