A quantitative method for the determination of benz- (a )anthracene (B (a )A) and benzo (a )pyrene (B (a )P) in mainstream and sidestream cigarette smoke by high performance liquid chromatography (HPLC) has been developed. Mainstream and sidestream particulate matter is collected on Cambridge filter pads. The polycyclic aromatic hydrocarbons (PAH) are extracted with cyclohexane and subjected to normal-phase chromatography to isolate target fractions which are concentrated and then diluted with acetonitrile or acetonitrile/water prior to reverse-phase analytical chromatography. The Kentucky Reference cigarette 1R4F and a cigarette which heats but does not burn tobacco (New Cigarette) developed at R. J. Reynolds Tobacco Company were analyzed and compared with respect to B (a )P and B (a )A in both mainstream and sidestream smoke.