The incidence of hospital-acquired infections in surgery fluctuates between 1.5 and 29%, the average infection is 5%. The most frequent hospital infections are: urinary tract infections, wound infections, respiratory tract infections, sepsis and infections of the skin. Escherichia coli and Staphylococcus aureus are most commonly isolated from the nosocomial infections. Hospital infections in surgery are of endogenous origin, i.e. from the organisms of the body itself (e. g. wound infections after intestinal interventions) or exogenous from direct or indrect contact. The most frequent route of transmission is by hands. Almost half of all hospital-acquired infections have their origin in surgery. Standards of prevention of hospital-acquired infections in surgery departments are described.