Expert committees on bacterial endocarditis prophylaxis have provided differing opinions on whether tracheal intubation is an 'at-risk' manipulation. We studied the incidence of bacteraemia after orotracheal and nasotracheal intubation. The study group comprised 110 patients who underwent surgery under general anaesthesia. Venous blood samples were collected from each patient at baseline and 30 s after intubation. Samples were processed with conventional microbiological techniques. Bacteraemia after tracheal intubation was detected in 13 patients (11.8%); six after orotracheal intubation and seven after nasotracheal intubation. Staphylococci and streptococci were the most commonly isolated bacterial species. Seven isolates (54%) were resistant to oxacillin. The incidence of bacteraemia was similar after orotracheal (12.0%) and nasotracheal intubation (11.7%). The recommendation for bacterial endocarditis prophylaxis with flucloxacillin when performing nasotracheal intubation, as put forward by the British Society for Antimicrobial Chemotherapy, needs further consideration.