This report gives a summary of the monitoring activities within the national Swedish contaminant programme in freshwater biota. It is the result from the joint efforts of: the Department of Applied Environmental Science at Stockholm University (analyses of organochlorines, flame retardants and perfluorinated compounds), Department of Chemistry at Umeå University (analyses of PCDD/PCDF) and the Department of Contaminant Research at the Swedish Museum of Natural History (co-ordination, sample collection administration, sample preparation, recording of biological variables, storage of frozen biological tissues in the Environmental Specimen Bank for retrospective studies, data preparation and statistical evaluation). The monitoring programme is financed by the Environmental Protection Agency (EPA) in Sweden. The data of concern in this report represent the bioavailable part of the investigated contaminants i.e. the part that has virtually passed through the biological membranes and may cause toxic effects. The objectives of the monitoring program in freshwater biota could be summarised as follows: