Inclusion Criteria:

1. Regular cigarette smokers smoking at least 5 cigarettes per day as derived by Time-Line Follow-Back method (Sobell et al., 1988). Average number of cigarettes per day (over past 30 days) will be used. Five cigarettes per day may seem low, but based on previous studies, adolescents tend to smoke fewer cigarettes per day as compared to adults.
2. Baseline urine cotinine level greater than 100 ng/ml.
3. Age range of 12 – 21
4. If under 18 yr. of age, parent(s) or guardian(s) able to participate in informed consent and initial assessment, or the participant must provide evidence of emancipated status.
5. For post menarchal female participants: agree to use birth control to avoid pregnancy.

Exclusion Criteria:

1. Active substance abuse/dependence (other than nicotine) within 2 weeks prior to participating in the study
2. Lifetime bipolar affective disorder (BPAD), psychosis, eating disorders. Bupropion may have adverse consequence on participants with these psychiatric diagnoses.
3. Current major depressive disorders. Since bupropion is also an antidepressant, this criteria is to minimize the confound of depressive disorder during the study. History of depressive disorders and current attention deficit hyperactivity disorder (ADHD) will not be an exclusion. We will use permuted block randomization procedure to balance the groups for ADHD.
4. Pregnancy or lactation. The safety of bupropion in pregnancy and during lactation is not well studied.
5. History of seizure disorder or predisposition to seizures (e.g., history of significant head trauma, currently taking medications that lower seizure threshold), since bupropion can lower seizure threshold.
6. History of severe renal, hepatic, neurological, or chronic pulmonary disease. This criterion was chosen due to the hepatic metabolism of bupropion.
7. Unstable medical problems
8. Allergy to bupropion
9. Current treatment with any other medication containing bupropion
10. Current treatment with any monoamine oxidase (MAO) inhibitors currently or within 2 weeks of starting the study since there may be serious and severe medical interactions between MAO inhibitors and bupropion SR.
11. Current treatment with nicotine replacement therapy (NRT)
12. History of intolerance or non-response to bupropion SR.
13. Current (past month) suicide ideation
14. Suicide attempt (past year)