Water and swab samples were collected from 13 hospitals and analyzed for Legionella counts. Legionella was detected in eight out of 13 hospitals and in 22 of 130 water and swab-collected samples. A total of 72.7% of the strains were L. pneumophila ser. 1, 22.7% were L. pneumophila ser. 2-14, and 4.5% did not belong to any of these groups. AFLP typing of the L. pneumophila ser. 1 strains generated two distinguishable AFLP types. There was no significant correlation to the sample type with Legionella recovery. Legionella isolation was more likely to occur in the cooling towers than the water system. Water temperatures of 30-40 degrees C seem to favor Legionella growth. Of the 265 serum samples taken from the medical and technical staff for the control of IgG titre, 89.4% were negative, 7.2% were positive, and for 3.4% the result was doubtful. No association between IgG titre and maximum observed level of Legionella occurrence was detected.