This study will investigate the efficacy of EVT 302, a potent and selective inhibitor of Monoamine Oxidase - B, in improving quit rates in chronic cigarette smokers who are motivated to quit smoking. EVT 302 will be compared to placebo both with and without open label nicotine replacement therapy.

Inclusion Criteria:

• Smoker of at least 10 cigarettes daily
• Motivated to quit smoking
• Reports at least one unsuccessful attempt to quit in the last 2 years
• In generally good health
• Provides written informed consent to participate in the sudy

Exclusion Criteria:

• Pregnant or nursing females.
• Women of child-bearing potential must agree to use acceptable contraceptive precautions (contraceptive pill and one barrier method)during the study and for 2-months thereafter
• History of anaphylaxis
• History of alcohol or drug abuse
• History of or current significant medical or psychiatric disorder
• History or presence of cataract or abnormality identified by slit lamp investigation
• Use of other MAO inhibitors, pethidine, SSRIs, tricyclic antidepressants,nasal or oral decongestants or cold medicines containing ephedrine, pseudoephedrine or other sympathomimetics.
• Any medicine contraindicated for use with MAO inhibitors.
• Have or be a carrier of hepatitis B or c or HIV 1 or 2
• Use of tobacco products other than cigarettes
• Use of nicotine replacement therapy in the past month
• Received an investigational drug in the past 30 days
• Previous participation in a study with a MAO-B inhibitor