An instrumental cigarette smoke monitor (CSM) system designed for human smoking studies has been developed and validated using a smoking machine as a human surrogate. The cigarette holder contains both smoke-mixing and flow-measurement orifices and a smoke-concentration sensor. Smoke flow through the holder and smoke concentration in the holder are determined simultaneously. The two signals are multiplied electronically and the product signal integrated. The integrated response is directly proportional to the amount of particulate matter collected immediately downstream of the holder, regardless of cigarette type or the particular way in which the cigarette is smoked. The CSM is sufficiently sensitive to quantitatively determine the amount of smoke TPM generated from cigarettes in the 1-mg Federal Trade Commission tar-delivery category.