A baseline study on the concentrations of contaminants in the Baltic Sea surface sediments was carried out in 1993. The study was initiated by the International Council for the Exploration of the Sea as a response to the request by the Helsinki Commission. All subareas of the Baltic Sea were covered. In addition to surface sediment samples for contaminant analyses, sedimentation rates were determined and a mineralogical study as well as a sediment characterization of the sediment cores were carried out. A recommendation is given on the use of sediment studies in relation to the monitoring of the state of the Baltic Sea.