Thirty-five surface sediment samples were collected from the northeastern coast of the lzmit Bay to apportion the sources of polycyclic aromatic hydrocarbons (PAH) entering the Bay. Samples were collected in February and June, 2002 and they were analyzed for 16 PAH compounds using HPLC-UV. Total PAHs ranged from 1.1 to 68.4 mu g g(-1)-dry wt. Both the factor analysis and the factor analysis-absolute factor score multiple linear regression analysis were applied to the results of 11 PAH compounds which were observed in more than 80% of the samples. From the factor analysis, two factors explaining 91.3% of the total variance were identified. The first factor was petrogenic and explained 76% of the variance. Except for the Anthracene, 57 to 85% of the lower molecular mass PAH compounds (from Fluorene to Chrysene) were contributed by this factor.