Chlorinated　polycyclic　aromatic　hydrocarbons　(ClPAHs)　with　three　to　five　aromatic　rings　have　been　documented　to　ubiquitously　occur　in　environmental　matrices.　In　this　study,　residual　concentrations　and　profiles　of　20　individual　ClPAHs　were　determined　in　35　surface　sediment　samples　from　Maowei　Sea,　a　semi-enclosed　shallow　inland　bay　located　in　the　northwestern　part　of　South　China　Sea.　The　concentrations　of　I　ClPAHs　pound　in　sediment　ranged　from　313　to　9650　pg/g　dw　with　a　detection　rate　of　43-100%.　Of　the　individual　ClPAH　congeners,　9-ClPhe　was　the　most　abundant　in　Maowei　Sea　with　the　concentrations　that　ranged　from　99.9　to　3610　pg/g　dw　(mean　1120　pg/g　dw).　High-molecular-weight　ClPAH　congeners　(four　to　five　rings)　were　predominant　in　sediments　from　sampling　locations　near　a　petrochemical　industrial　complex,　whereas　low-molecular-weight　ClPAH　congeners　(three　rings)　were　predominant　in　sediments　from　estuarine　and　mangrove　locations.　A　positive　matrix　factorization　(PMF)　model　in　combination　with　dioxin-like　toxic　equivalency　quotient　(TEQ)　results　was　used　to　apportion　sources　of　ClPAHs.　Vehicular　emission,　combustion/chemical　industrial　processes,　and　two　other　unknown　sources　accounted　for　40.1,　25.5,　20.8,　and　13.6%,　respectively,　of　ClPAH　sources　in　sediment;　their　contribution　to　TEQs　in　sediments　were　24.2,　40.5,　19.3,　and　16.0%,　respectively.　Further　investigations　are　needed　to　elucidate　potential　sources　and　ecological　risks　of　ClPAHs　in　sediments.