Although physicians routinely advise postcardiac event patients to stop smoking, the effect of a modified advice format targeting specific health concerns has not been investigated. Also, no studies of cessation advice with cardiac patients have used biochemical verification of self-reported abstinence. The present study included 48 veterans with a history of smoking and cardiac problems; of these, 31 were smoking and 17 were abstinent at initial assessment. Alveolar carbon monoxide (COa) levels served to: (1) augment cessation advice by demonstrating smoking risks and cessation benefits specific to cardiac patients and (2) verify self-report. At 12 months followup, following cessation advice, 18% of the abstinent subjects had resumed smoking while none of the smokers had become abstinent. Those who maintained abstinence significantly increased their estimates of the contribution of smoking to their cardiac problems whereas those who continued to smoke showed no change.