Objectives. This study examined the prevalence of occasional smoking i
n a population of working adults, compared the characteristics of occa
sional and daily smokers, and prospectively examined the long-term smo
king patterns of occasional smokers. Methods. At 32 Minnesota work sit
es, 5681 randomly selected workers were surveyed at baseline; 5248 of
these were surveyed again 2 years later. A cross-sectional sample of 5
817 workers was also surveyed at follow-up. Results. Occasional smoker
s constituted 18.3% of all smokers in the baseline sample and 21.5% of
all smokers in the cross-sectional sample surveyed 2 years later. Bas
eline occasional smokers were significantly more likely than daily smo
kers to have quit at follow-up. Job monotony or repetitiveness was rel
ated to an increase to daily smoking at follow-up among baseline occas
ional smokers, and a change to a more restrictive workplace smoking po
licy was associated with quitting. Conclusions. The results confirm th
at a substantial proportion of smokers are low-rate users and suggest
that the proportion may be rising. Further research on this group is w
arranted.