The content of various phosphorus forms in sediments and the content of iron in interstitial waters were measured in sediment samples collected in the Gulf of Gdansk in March 2001. The studies showed that the greatest amounts of the total phosphorus and total dissolved iron were present in the uppermost sediment layer, and their respective concentrations ranged from 203,99 mumol?g-1d.w. to 1894,02 mumol?g-1d.w., and from 0,02 mumol?dm-3 to 4,68 mumol?dm-3. The contents of these parameters were directly connected with the type of sediment - the greatest concentrations were measured in fine sediments. The analysis of multiple correlation coefficients demonstrated that in over 90% of cases the concentration of phosphorus bound with iron depended on: the sediment type and its humidity, the content of organic matter, and the concentration of the total iron dissolved in the interstitial waters.