Based on the frequency of the isolated bacteria the antibiotics and chemotherapeutics commonly used in infections of the urinary tract are discussed. It turns out that ampicillin and sulphamethoxazole-trimethoprim are still the drugs of choice in the treatment of these bacterial diseases. A true advance is achieved by the introduction of carbenicillin and the new aminoglycoside amikacin. Carbenicillin can be used in Pseudomonas infections and is characterized by its low toxicity. Amikacin is the drug of choice against aminoglycoside-resistant gramnegative bacteria.