Problem/Objective: Fear of weight gain is common among smokers and negatively associated with motivation and abstinence. No studies have evaluated the impact of weight concerns for those receiving Zyban and counseling. We will 1) review the literature on cessation programs for those with weight concerns, 2) describe characteristics of smokers with weight concerns enrolled in a combined treatment study, and 3) determine the impact of weight concerns on outcomes. Methods: Data come from an effectiveness trial (n=1524) comparing different dosages of Zyban and counseling (5 calls vs. tailored mail). Results: weight concerns were more common in older men and younger women. Those with weight concerns (38% M, 70% F) had higher BMI (28 vs. 26), considered themselves overweight (67% vs. 35%), were dieting (24% vs. 6%), reported higher stress and depression and prior relapse due to weight gain (31% vs. 3%). At 12 months, more weight concerned participants reported dieting (52% vs. 37%) and exercising more in the prior year (34% vs. 28%). While groups did not differ on quit rates at 12 months (28%), those with weight concerns relapsed sooner (57 vs. 71 days) and 49% (vs. 41%) reported gaining weight. Conclusions: the benefits of Zyban and counseling may be reduced for smokers who are overweight or fear gaining weight. We will discuss mechanisms to explain the findings. Learning objectives: understand weight concerns and interventions that can reduce weight gain without impacting cessation efforts. This knowledge can help in developing innovative recruitment and treatment strategies.