Abstract: Bacteremia is the presence of bacteria in the blood. The immune response to the presence of bacteria in the blood can cause sepsis and septic shock which results in a high mortality rate. For an adequate treatment of sepsis, a severe clinical condition which requires a timely intervention with appropriate antibiotic therapy it is of great importance to know the most frequent causes. Blood culture is considered the best option for the detection and isolation of microorganisms from the blood as well as a microbiological proof of a present bacteremia. The aim of this study is to ascertain the causative bacterial agents in normally sterile fluids as well as their susceptibility to antibiotics within the period of 2011-2015 in the District Hospital of Čakovec. Material and Method: Data on processed blood cultures within the period of 2011 – 2015 were collected form the Microbiological Laboratory Institute for Public Health of the District of Međimurje, which carries out the microbiological analysis of all samples taken from hospitalized patients in the District Hospital of Čakovec. For data interpretation methods of descriptive statistics were used. Results The number of processed blood samples in the Distirct Hospital Čakovec is between 1286 and 1508 pairs of blood cultures. The relative share of positive samples is between 14% and 21%, while the relative share of contaminated samples accounts to 4 -7%. The three most frequent bacteria among the isolates from the blood cultures are E.coli; S.aureus and K.pneumoniae. With E. coli as the most frequent bacterial isolate from the blood cultures a growing resistance to co-amoxiclav from 13% in 2011 to 30% in 2015 can be perceived. The susceptibility to the third generation of cephalosporine (ceftriaxone) is mainly under 10%. The susceptibility to gentamicin has been very low in the past three years. Unfortunately, the resistance to quinolone has been above 10% in all years except 2014. To carbapenem no resistance has been registered. Conclusion It is very important to learn about the expected pathogens and follow their susceptibility to antibiotics to, hence, be able to develop a good empiric therapy. The communication between the medical staff of the hospital departments and the staff of the Microbiological Laboratory contributes to the improvement of the followed indicators, respectively to the reduction of the contamination rate. Reliable study results influence the correct choice of antibiotic therapy as well as, consequently, the resistance of bacteria to antibiotics.