Currently, a persistent growth of bacterial resistance to antibiotics takes place. Multiresistant bacterial strains thus represent a serious danger for therapy in practice. The aim of the study was to characterize the multiresistant Gram-negative bacteria and to judge their antibiograms by using the minimum inhibition concentrations (MIC). At the same time the study evaluates the relations to the most frequent diagnoses and epidemiologic data concerning the occurrence of these strains in different clinical cases treated at individual departments of the Faculty Hospital in Olomouc. Out of the total of 4.988 strains of Gram-negative rods, the number of isolated multiresistant strains reached 316 (6.3%). Individual bacterial species were isolated in the following order: Pseudomonas aeruginosa (28.8%), Enterobacter cloacae (23.4%) and Acinetobacter Baumannii complex (Acb complex) (18.7%). The most frequent occurrence of investigated bacteria was registered at the departments in the following order: urology (45.9%), internal medicine (18%), paediatrics (13.6%), and surgery (11.1%). The most frequent diagnoses based on positive cultivation of these bacteria were the infections of the urogenital tract (53.8%), postoperative infections (16.8%), and the infections of the upper respiratory ducts (7.3%). 64.2% of strains were cultivated from urine, 16.1% from pus, and 6.9% from swabs taken from the upper respiratory ducts. (Tab. 8, Ref. 18.).