Alkylphenol ethoxylate (APEOs) and bisphenol A (BPA) are well known as endocrine disrupting compounds. Among sources of these compounds within receiving waters, wastewater treatment plant effluents have been widely studied. However, Although APEOs and BPA are regularly quantified within wastewater and to a lesser extent in runoff, few studies deal with their discharges by combined sewer overflows. In this context, this study was launched to investigate the concentrations and the mass loads discharged per year by CSO in the Seine River. Therefore, discharges occurring at the one of the most important CSOs of Paris conurbation from June to November 2010 were sampled. During this period, eight events were collected by automatic samplers and even mean sample were analyzed in laboratory using liquid chromatography coupled to a tandem mass spectrometry. The first results highlight an important contamination of CSOs by BPA and levels of APEOs close to those reported in wastewaters. At the annually scale and according to our mass load calculation, CSOs do not appear as a relevant source of BPA and APEOs within the Seine River.