Monoclonal antibodies or antigen-binding fragments thereof that bind to Clostridium difficile (C. difficile) toxin A or toxin B and methods of using the same to detect or treat C. difficile infections and/or C. difficile-associated disease. C. difficile is a gram positive, anaerobic bacterium that causes gastrointestinal disease in humans. The bacteria are transmitted through feces and spread to food and other surfaces when people who are infected do not thoroughly wash their hands.