Changes in organic carbon and nitrogen concentrations as well as the atomic C/N ratio in suspended matter and vertical profile of surface sediments (0-5cm) from different sedi-mentation areas of the Gulf of Gdansk (Southern Baltic) were studied in late spring 1995. Concentrations of organic carbon and nitrogen in suspended particulate matter (SPM) varied between 0.14 and 1.20 mg dm-3, respectively. The deeper parts of the Gulf of Gdansk (station U20) and station remaining under the direct influence of the riverine discharges (W2 and JR), are characterised by nigh values of organic carbon and nitrogen concentrations. C/N ratio in SPM in euphotic layer of the water column reveals significant spatial variability connected with organic matter origin; the highest values (10.11-10.46) were observed at sta-tions: W2 and JR which remained under riverine runoff. At the other sampling stations located in the eastern part of Puck Bay and open part of the Gulf of Gda?sk C/N ratio reached values: 8.93 - 9.87, what indicates a bigger proportion of the autochthonous organic matter. Variability in concentrations of organic carbon and nitrogen in surface sediments is controlled by sediment dispersion and its sorption properties, location of the station in respect of the main sources of the terrestrial and riverine discharges. The lowest concentrations of organic carbon and nitrogen were observed in sandy sediments, while the highest ones in clay sediments of the deep open part of the Gda?sk Basin. The highest values of C/N ratio (11.56-13.49) in the surface sediments were observed at sta-tions being under direct influence of rivers (W2, JR), while the lowest ones (8.89-9.61) oc-curred in sediments of the open part of the Gulf of Gdansk, which is to the lesser extent influ-enced by the riverine inflow. At station JR (sandy sediments), located in the inner Puck Bay, high C/N ratio as well as rela-tively large content of both organic carbon and nitrogen in surface sediments could also be influenced by migration of highly degraded refractory organic matter from deeper sediment layers (peat and calcareous gyttja).