Smoking remains the leading cause of preventable death in the U.S. Heavy alcohol use frequently co-occurs with smoking and is associated with greatly reduced odds of successful smoking cessation. Evidence also suggests alcohol use may be involved in about a tburth of all smoking lapses. Despite these associations and the demonstrated efficacy of brief interventions to reduce alcohol use in a variety of patient populations, no protocols have been established for addressing heavy alcohol use during smoking cessation treatment. The overall aim of this project is to improve smoking cessation treatment outcomes among the substantial portion of smokers who drink heavily. The study employs a between-groups design in which 250 smokers who currently drink heavily (>14 drinks per week or greater than or equal to 5 drinks per occasion at least once per month for men; >7 drinks per week or greater than or equal to 4 drinks per occasion at least once per month for women) but do not meet diagnostic criteria for alcohol dependence will be assigned randomly to either: (a) individual standard smoking cessation treatment [ST] or (b) individual standard smoking cessation treatment that incorporates a brief intervention to reduce alcohol use [ST-BI]. Treatment will be delivered in four sessions over a three-week period. All participants will be provided transdermal nicotine patch and be followed for one year. The primary aim of the study is to test the hypothesis that ST-BI, compared to ST, will result in higher rates of abstinence from smoking at post-treatment and at 8-, 16-, and 26-week follow-ups. The secondary aims test whether ST-BI results in greater reductions in alcohol consumption and whether the effects of ST-BI on smoking outcomes are mediated by reduced risk of smoking lapses in alcohol use situations. Tertiary analyses examine moderators of risk for alcohol-related smoking lapses and predictors of change in drinking. If successful, this study will establish a promising treatment approach for the substantial portion of smokers who drink heavily. This study also will contribute valuable knowledge about the mechanisms of change in alcohol and tobacco-related behaviors. Because almost all funded and published studies on smoking in substance abuse populations have focused on alcoholics in alcohol treatment, nondependent heavy drinkers, who are unlikely to present in traditional substance abuse treatment settings, have received little research attention. Developing effective interventions that address alcohol use during smoking cessation treatment can make a major public health impact on this large, yet neglected, subgroup of smokers.