The curves of the cumulative smoke volumes (CSV), as determined by the number of puffs, the puff intervals, the single puff durations, and puff volumes, of 108 nondeprived smokers who smoked two personal brand cigarettes revealed statistically distinct clusters. Pronounced nonlinear increases in the puff intervals and modest decreases in the puff volumes were seen generally, but they varied in extent between clusters as did the number of puffs and estimated mouth intake of nicotine. Most clusters (representing 80% of the smokers) did not deviate significantly from a linear development of the CSV curves, and those that did were characterized by particularly short puff intervals. Most of the subjects moved from the first to the second cigarette into clusters of similar shapes. However, none of these conclusions showed any relation either to the nicotine yield of the cigarettes or to the pre-to postsmoking delta tidal CO. It was therefore concluded that the sensory consequences of the physicochemical changes in smoke composition between the first and last puff or other as yet unknown psychological factors are more likely candidates than nicotine satiation for explaining the typical changes in puffing behavior along burning time of a cigarette.