Development of bacterial resistance to antibiotics brought many problems among which the most important are infections caused by multiple resistant bacterial strains. Bacteria have amazing 'equipment' of biochemical and genetic mechanisms to ensure evolution and spread of antibacterial resistance genes. The results obtained from very important projects all around the world and in our country show that bacterial resistance to certain groups of antibiotics is very high (up to 100%), because of uncritical use of antibiotics out of these groups. Due to the development of resistant bacterial strains, we may soon run out of efficient antibiotics for some patients. Outcome of the race between science and pharmaceutical industry on one side, and bacterial adaptation trough acquisition of resistant genes on the other side, is very uncertain. Actions must be taken to slow down the evolution and spread of antibiotic resistance genes in which the major single factor is the proper use of antibiotics in human medicine, veterinary medicine and agriculture, respectively.