The purpose of this study was to screen all cases of Clostridium difficile-associated disease during a 2-year period in a geriatric hospital to determine the incidence and clinical characteristics related to this risk. Twenty percent of suspected cases were diagnosed as positive and analyzed. The C difficile disease-associated clinical factors were ischemic heart disease and chronic obstructive pulmonary disease. Use of acetylsalicylic acid, other nonsteroidal anti-inflammatory drugs, and steroids were more frequently found in the non-C difficile group. There were fewer cases in men than in women and more in patients residing in skilled nursing wards.