Puffing behavior (number of puffs, puff interval, puff duration, peak pressure, latency to peak pressure, average and total puff volume) was measured in 67 dependent male and 43 dependent female smokers when they smoked two cigarettes of their habitual brand under laboratory conditions. Test-retest reliability for the two cigarettes was high, and factor analysis showed that puff shape, puff volume, and puff frequency accounted for about 50% of variation obtained with the different puffing variables. Expiratory tidal CO levels increased with the number of cigarettes smoked before the tests and with the intensity of the smoking habit, but pre- to postsmoking delta tidal CO differences were similar for smokers of all types of cigarettes (0.1 - 1.7 mg standard machine smoking nicotine yield). Volume compensation for differences of smoke yield of the cigarettes was generally more pronounced in women than in men and, additionally, it was more pronounced for cigarettes with standard smoke nicotine yield below 0.9 mg than for cigarettes with standard smoke nicotine yield above 0.9 mg for both sexes. Only for women, partial correlation procedures suggested that nicotine might be more important in determining puffing behavior than CO and condensate yield, but there were also no women smoking the strongest cigarettes (1.3 - 1.7 mg nicotine yield). For both sexes, no compensation by adjusting the number of cigarettes smoked daily was obtained. Personality ratings, pulmonary functions, and cardiovascular functions were not, or only inconsistently, correlated with puffing behavior or type of cigarette.