The EU Water Framework Directive (2000/60/EC) (WFD) commits EU member states toachieve good environmental status of all water bodies by 2015. One of several ways pollutants end up in our waters is through municipal wastewater treatment plants (MWWTPs),which are obliged to report releases of compounds listed by the European Pollutant Release and Transfer Register (E-PRTR). Most environmental reports from Swedish MWWTPs included in E-PRTR have not reported released amounts of several of the organic compounds found on the E-PRTR list, possibly due to difficulty of quantification in the WWTP effluent. Previous studies have shown that the release of several of these compounds could be close to, or above the reporting limits, thus methods for estimating them are required. Chemical fate models, specially designed to simulate fate processes in wastewater treatment plants may be helpful tools for M-WWTPs when estimating their releases. In this report the applicability of the STP-EX model to simulate releases from Swedish M-WWTPs is evaluated by first comparing the theoretical results from four different M-WWTPs for 18 chemicals/chemical groups, and then through model evaluation by comparing modeled and measured results from Bromma M-WWTP for PAHs, alkylphenols and PBDEs. Overall the model can be a helpful tool to give an indication of annual released amounts of organic pollutants from Swedish M-WWTPs. Still, releases to the effluent predicted from both incoming amounts and amounts in sludge (primary + secondary) at Bromma M-WWTP results in an underestimation for almost all included substances. The most accurate estimations are for PAHs, where the water/sludge ratio predicts the released amounts within a factor of 2. For PBDEs and alkylphenols the difference between measured and predicted releases varies with a factor of 5-370, with an average of 45 for OUT/IN and 103 for water/sludge. The largest differences are for BDE-85.