Dental procedures may lead to a transient bacteraemia lasting for up to 30 minutes. Of the numerous cases of total hip arthroplasty (THA) reported which have been infected from haematogenous sources, dental procedures have been involved only infrequently. We reviewed the records of 2973 patients after THA. Of the late infections identified in 52 patients, three (6%) were strongly associated with a dental procedure. Infection was diagnosed by culture from the affected joint; Streptococcus viridans was identified in two cases and Peptostreptococcus in one. One patient had diabetes mellitus and another rheumatoid arthritis, both conditions predisposing to infection. The dental operations all lasted for more than 45 minutes and no patient received perioperative antibiotics. Infection of a THA after dental procedures is more common than has been previously suspected. Patients with systemic disease, or who are undergoing extensive procedures, should be considered for prophylactic antibiotic treatment.