All smokers admitted to three hospitals over a 27-month period were identified as part of the admissions process. Those who met eligibility requirements were randomly assigned to one of three treatment conditions: minimal care; a low intensity intervention whose centerpiece was brief firm advice by health care providers and labelling of the smokers' charts (PA intervention); and the PA intervention plus more intensive counseling and follow-up after discharge performed by a research nurse (PA+NC intervention). Intervention components included provision of smoking cessation manuals and training of health care providers (all conditions); structural reminders to health care providers to give smoking cessation advice and provision of smoking cessation advice by a variety of health care providers on several different occasions (PA and PA+NC); and in-hospital counseling tailored to patient characteristics, feedback about a biological marker of smoking, a stepped care approach, and follow-up telephone counseling after discharge (PA+NC only). All participants were followed for twelve months after discharge from the hospital to examine the relative effectiveness and cost-effectiveness of the smoking cessation programs. In addition, information about smoking cessation advice given to study patients by primary care physicians in the twelve months after discharge from hospital was gathered to assess the possible synergistic effects of advice provided in in-patient and out-patient settings.