An understanding of the factors influencing respiratory deposition of cigarette smoke in smokers is needed to accurately control this important source of respiratory exposure in epidemiological studies of workers. Only a few studies have characterized the deposition of cigarette smoke in smokers and these involve methods that interfere with normal smoking. A technique for measuring puff volume, inhaled amount, and respiratory deposition of cigarette smoke particulate phase has been developed. It provides satisfactory accuracy (±10%) and causes minimal disruption of normal smoking pattern. The technique captures exhaled smoke with an exhaust hood and establishes the amount of inhaled smoke by monitoring puff volume, puff duration, and puff timing and replaying the exact smoking sequence with matched cigarettes. Mass of captured cigarette smoke is evaluated by fluorophotometry. Preliminary trials with 11 paid volunteers gave an average puff volume of 53 mL and smoke deposition ranged from 22% to 75% with an average of 47%. Measured depositions are lower than previously published values and higher than would be predicted for submicrometer sized particles during normal breathing.