Clostridium difficile is a well-known cause of hospital-acquired infectious diarrhea and is associated with increased health-care costs, prolonged hospitalizations, and increased patient morbidity. Previous antimicrobial use, especially use of clindamycin or ciprofloxacin, is the primary risk factor for development of C. difficile-associated diarrhea (CDAD) because it disrupts normal bowel flora and promotes C. difficile overgrowth. Historically, CDAD has been associated with elderly hospital in-patients or long-term--care facility (LTCF) residents. Since 2000, a strain of C. difficile that has been identified as North American pulsed-field type 1 (NAP1) and produces an extra toxin (binary toxin) and increased amounts of toxins A and B has caused increased morbidity and mortality among hospitalized patients. During 2005, related strains caused severe disease in generally healthy persons in the community at a rate of 7.6 cases per 100,000 population, suggesting that traditional risk factors for C. difficile might not always be factors in development of community-associated CDAD (CA-CDAD). Cases of CA-CDAD are not nationally reportable, and population-based data at a statewide level have not been reported previously. In 2006, the Connecticut Department of Public Health (DPH) implemented a statewide surveillance system to assess the burden of CA-CDAD and to determine the descriptive epidemiology, trends, and risk factors for this disease. This report describes that surveillance system and summarizes results from the first year of surveillance. The findings indicated the presence of occasionally severe CDAD among healthy persons living in the community, including persons with no established risk factors for infection. Clinicians should consider a diagnosis of CA-CDAD in outpatients with severe diarrhea, even in the absence of established risk factors. In addition, continued surveillance is needed to determine trends in occurrence and whether more toxigenic strains are having an increasing impact in the community and in the hospital setting.