The results of the epidemiological analysis of morbidity in purulent septic infection in a cardiosurgical hospital during the period of 1990-1963 is presented. As revealed by this analysis, until 1993 the dominating causative agent of this infection was Pseudomonas aeruginosa O16, and since 1994 Staphylococcus epidermidis prevailed. The morbidity dynamics for several years and during individual years is shown. The main risk factors were established. The reanimation department was found to be the main areas where the contamination of patients occurred.