During POLRODEX'96 experiment (July/August 1996), the extensive measurements of hydro-dynamic conditions in the Gulf of Gdansk were carried out. Short-term and long-term measure-ments involved the registration of currents, salinity, water temperature and changes of the water level at the open sea. Hydrological and meteorological data collected were then used for the de-velopment of a numerical model for the Gulf of Gdansk. Comparison between modelled and calculated distributions (verticals, time series) leads to a conclusion that the proposed model predicts the actual hydrodynamic conditions with acceptable accuracy. Main discrepancies may result from the assumed initial and open boundary conditions.