In late 2001, MDPH was awarded funding from the United States Environmental Protection Agency (USEPA) that partially supports Department efforts to (1) develop an inventory of marine bathing beaches, (2) compile monitoring data, and (3) to conduct assessments of those beaches identified as high-risk. The MDPH Bureau of Health Quality Management, Division of Community Sanitation (DCS), conducted a survey of Massachusetts municipalities in order to establish an inventory of all public and semipublic marine and freshwater beaches. They also collected data from reporting local health departments and other agencies for the 2002 bathing season and provided these data to the Departments Bureau of Environmental Health Assessment (BEHA), Environmental Toxicology Program (ETP). In 2003, MDPH used Beach Grant funds to contract five laboratories (Barnstable County Health Department Laboratory, Town of Chatham Water Quality Laboratory, Dukes County Testing Laboratory, New Bedford Health Department Laboratory and G and L Laboratory) to process regular weekly samples for public, marine beaches in Massachusetts, and to report the data directly to MDPH. Freshwater data were reported by local Boards of Health, as in the past. This report presents the results and analysis of this 2003 data from Massachusetts marine and freshwater bathing beaches.