Concentration and composition of chloronaphthalenes (PCNs) were determined in blubber of two male and two female porpoises from the Gulf of Gdańsk. Porpoises examined died in the fishing nets in 1992. Polychlorinated naphthalenes were determined using capillary gas chromatography and high resolution mass spectrometry (HRGC/HRMS) after nondestructive cleanup with polyethylene membrane, and pre-separation of planar compounds on carbon HPLC column. 28 peaks from chloronaphthalenes were identified and quantified on a chromatogram. Concentration of total PCNs in blubber of male porpoises were 1.7-2.4 ng/glipid weight, and of female 2.0-2.4 ng/g. Among of the PCN congeners found 1,2,3,4,6,7-/1,2,3,5,6,7-hexachloronaphthalene (PCN nr 66/67) and 1,2,4,6-/1,2,5,7-tetrachloronaphthalene (PCN nr 3/34/37) were dominating compounds, followed by 1,4,6,7-tetrachloronaphthalene (PCN nr 47), 1,2,3,5-/1,3,5,8-tetrachloronaphthalene (PCN nr 28/43) and 1,2,3,5,7-/1,2,4,6,7-pentachloronaphthalene (PCN nr 52/60), and others were minor contributors.