A per-puff PAH analysis technique was developed in our lab and applied to study PAH formation and distribution in the smoking process. An impaction trap was used to collect the total particulate matter (TPM) from a single puff of smoke. The TPM was then dissolved in a mixture of solvents and analyzed by GC-MS using selective ion monitoring mode. Five PAHs were measured in this study, including naphthalene, phenanthrene, pyrene, fluoranthene, and benzo[a]pyrene. Results on PAH levels in each puff of a reference cigarette will be discussed.