During a 5-month period, Hansenula anomala (H. anomala), an opportunistic fungus, caused an outbreak of infections in eight adult patients treated at a surgical intensive care unit (ICU). The source of the infections and route of transmission could not be identified. A case-control study included 32 patients treated simultaneously at the surgical ICU. Univariate analysis pointed to the following significant risk factors: blood alkalosis, reduced urea, duration of hospitalization, bacteremia and colonization with Pseudomonas aeruginosa, and an APACHE II score >17 (during bacteremia or fungemia). The stepwise logistic regression multivariate analysis showed only the duration of blood alkalosis to be significant in case patients.