Smoking is highly prevalent among people with schizophrenia, and little is known about factors that affect smoking in these patients. One basic question is whether smoking behavior differs for smokers with schizophrenia compared to equally nicotine-dependent smokers who do not have a major mental illness. In this study, 20 smokers with schizophrenia or schizoaffective disorder (SCZ) and 20 non-psychiatric smokers (CON) underwent smoking topography assessments. The groups were matched on age, gender, daily smoking rate, years of regular smoking and nicotine dependence rating. Results indicate that, compared to the CON participants, the SCZ participants smoked significantly more total puffs (SCZ: 58.5 +/- 48.3; CON: 21.3 +/- 9.4) and puffs per cigarette (SCZ: 12.3 +/- 6.0; CON: 8.9 +/- 2.3) and had shorter inter-puff intervals (SCZ: 21.9 +/- 9.7 s; CON: 42.0 +/- 21.5 s), larger total cigarette puff volumes (SCZ: 583 +/- 169 ml; CON: 429 +/- 159 ml) and higher carbon monoxide boosts (SCZ: 3.8+/-5.4 ppm; CON: 1.0 +/- 2.5 ppm). Test-retest reliabilities were good to excellent for most smoking measures in both groups. These findings suggest that smokers with schizophrenia smoke more intensely than matched non-psychiatric smokers and that their smoking behavior is reliable when assessed under laboratory conditions.