This document specifies a method for the determination of benzo[a]pyrene (B[a]P) in the total particulate matter (TPM) of cigarette mainstream smoke using gas chromatography/mass spectrometry (GC/MS) with methanol as extraction solvent. This method is specified using ISO 3308 smoking parameters. An alternative method for the determination of B[a]P is specified in ISO 22634-2 with a different clean-up using cyclohexane solvent and a shorter total analytical time.