Pharmaceuticals, hormones, and other known or suspected endocrine disrupting compounds (EDCs) have been widely detected in various waters throughout the world. Prior to this study, however, sampling for these substances was rather limited within Alberta. In 2002 and 2003, due to concerns about potential impacts on humans, livestock, aquatic organisms, and wildlife, Alberta Environment collected wastewater treatment plant (WWTP) effluents and receiving river water from numerous locations throughout the Province and analysed them for a broad range of organic wastewater contaminants (OWCs). This initial survey, encompassing an assortment of pharmaceuticals, antibiotics, steroids, surfactants, and plasticizers, was designed to determine which compounds are released by WWTPs in Alberta and to assess their presence in receiving river waters. Results of this study indicate that many of the 1 05 compounds and isomer mixtures that were tested for occur with some regularity in Alberta WWTP effluents and can be detected in the associated receiving rivers. In the majority of cases, concentrations of target analytes in receiving waters at well-mixed downstream sites were either below detection or several orders of magnitude lower than the same compounds in corresponding WWTP effluents. Certain groups of pharmaceuticals, namely the quinolone and tetracycline antibiotics, were virtually absent in surface waters, while others, including acidic pharmaceuticals, neutral pharmaceuticals, and sulfonamide antibiotics, were markedly lower in rivers than they were in effluents. Similarly, those EDCs that occurred at measurable concentrations in effluents were typically much reduced or below detection in downstream river water. All of the phthalate esters, one of nine monophthalate esters, and all nonylphenol ethoxylates analysed were found in effluents and, albeit at greatly reduced levels, in receiving waters. At present, surface water guidelines have not yet been established for the vast majority of compounds examined during this study. Nonetheless, the Canadian Council of Ministers of the Environment nonylphenol guideline for the protection of aquatic life (1.0 pg/L) was exceeded by 0.4 pg/L in the Oldman River. However, since toxic equivalents for each river were calculated based on data from a single sample collected at a single point in time, they should be viewed with caution. A need for additional monitoring of OWCs in Alberta's surface waters is indicated.