The treatment of infections is one of the central elements in post-operative intensive care and contributes significantly to outcome. Measures of quality of antibiotic therapy include survival, duration of ICU or in-patient stay and rates of organ failure, antibiotic resistance or nosocomial infection. The pre-requisites for antibiotic prescribing in the intensive care unit are as follows: the treatment has to be started early, the antibiotic must be effective against probable causative organisms, the patient's risk factors for infection with multi-drug resistant organisms must be taken into account, local patterns of resistance must be known, an effective dosage must be used and the duration of therapy should be adjusted to the patient's risk factors and probable causative organisms. The multiplicity of factors which must be taken into account when determining timely empirical therapy and the fact that this must be possible at any time of the day, make local standard operating procedures for antibiotic prescribing imperative. These standards should reflect local resistance patterns and should be regularly reviewed. The aim of this educational article is to portray a selection of the pre-requisites and strategies available in the treatment of infections with antibiotics in intensive care medicine.