Pseudobacteraemia occurs when bacteria isolated from blood cultures have originated from outside the patient's bloodstream. Failure to recognize that pseudobacteraemia is taking place and is not true infection may result in patient morbidity, unnecessary therapy and a significant waste of health care resources. Pseudobacteraemia may occur as a result of contamination introduced at any stage of blood culturing, from taking the blood to processing it in the laboratory. In most reported cases, contamination has occurred as a result of faulty aseptic technique, and thus pseudobacteraemia is usually preventable. Episodes of pseudobacteraemia require prompt investigation, but their recognition may be extremely difficult. Here we review pseudobacteraemia and recommend guidelines for its recognition, investigation and prevention.