OBJECTIVE To explore the nature of emergency department (ED) visits for dental problems of nontraumatic origin in Canada's largest province, Ontario. METHODS The Canadian Institute for Health Information's National Ambulatory Care Reporting System was used, which contains demographic, diagnostic, procedural and administrative information from hospital-based ambulatory care settings across Ontario. Data of fiscal years 2003/04 to 2005/06 were included for emergency visits that had a main problem coded with an International Classification of Diseases - 10th edition code in the range K00-K14, representing diseases of the oral cavity, salivary glands and jaws. Volumes are presented by a number of different factors in order to describe patient and visit characteristics. RESULTS During this period, there were a total of 141 365 ED visits for dental problems of nontraumatic origin in Ontario, representing an estimated 116 357 persons. Approximately half of all visits (54%) were made by those 20 to 44 years old, and associated with periapical abscesses and toothaches (56%). The great majority (78%) were triaged as nonurgent, and most (93%) were discharged home. CONCLUSIONS ED visits for dental problems of nontraumatic origin are not insignificant. Over the study period, these visits were greater than for diabetes and hypertensive diseases. Policy efforts are needed to provide alternative options for seeking emergency dental care in Ontario.