Risk factors of severity (need for surgical intervention, intensive care or fatal outcome) were analysed in hospital-acquired Clostridium difficile infection (CDI) in a 777-bed community hospital. In a prospective analytical cross-sectional study, age (≥ 65 years), sex, CDI characteristics, underlying diseases, severity of comorbidity and PCR ribotypes were tested for associations with severe CDI. In total, 133 cases of hospital-acquired CDI (mean age 74.4 years) were identified, resulting in an incidence rate of 5.7/10,000 hospital-days. A recurrent episode of diarrhoea occurred in 25 cases (18.8%) and complications including toxic megacolon, dehydration and septicaemia in 69 cases (51.9%). Four cases (3.0%) required ICU admission, one case (0.8%) surgical intervention and 22 cases (16.5%) died within the 30-day follow-up period. Variables identified to be independently associated with severe CDI were severe diarrhoea (odds ratio [OR] 3.64, 95% confidence interval [CI] 1.19-11.11, p=0.02), chronic pulmonary disease (OR 3.0, 95% CI 1.08-8.40, p=0.04), chronic renal disease (OR 2.9, 95% CI 1.07-7.81, p=0.04) and diabetes mellitus (OR 4.30, 95% CI 1.57-11.76, p=0.004). The case fatality of 16.5% underlines the importance of increased efforts in CDI prevention, in particular for patients with underlying diseases.