Antibiotic resistance is the resistance of bacteria to antibiotics i.e. their abitility to grow in the presence of antibiotics. The development of antibiotic resistance is an example of natural selection where the antibiotics represent a selective pressure and only those bacteria that have resistance genes will survive. Antibiotic resistance has been a part of the evolution of bacteria for a long time already but the modern lifestyle, irrational and excessive use of antibiotics accelerate the development and spread of antibiotic resistance. There are two types of antibiotic resistance: intrinsic, which is a result due to the lack of the antibiotic's target in the bacteria and „acquired“ which can be a result of mutations in the bacterial genome or a result of horisontal gene transfer (transformation, transduction and conjugation). The mechanisms of „acquired“ resistance are: enzymatic modification of the antibiotic, change in the molecular structure of the target molecule, change in the permeability of the bacterial outer membrane and efflux of the antibiotic. Antibiotic resistance is a big global problem because the treatment of common bacterial infections became more difficult. To reduce the problem of antibiotic resistance in the future, there are some precautions that need to be taken: reducing the consumption of antibiotics, educating the population and encouraging further research with the aim of better understanding mechanisms of antibiotic resistance and producing new and more efficient antibiotic to which bacteria will not be resistant, for at least some time.