Clostridium difficile is a Gram-positive, spore-forming, anaerobe and is the leading cause of antibiotic-associated diarrhea, pseudomembranous colitis, and toxic megacolon. Essential to the lifestyle of C. difficile is the ability to form a metabolically dormant spore, germinate, and grow out upon appropriate signals and elicit disease with the secretion of two toxins. To aid in the study of this organism, this unit describes the growth and maintenance of C. difficile. Included are methods to isolate C. difficile from environmental samples, grow in laboratory medium, and produce and purify spores.