Studies determining anesthesia mortality rates in dentistry have been published, yet a similar investigation has never been conducted in Canada. Therefore the objective of this study was to determine the incidence of mortality when general anesthesia or deep sedation was administered by qualified dentists in the province of Ontario. Mortality data were obtained from the years 1973 to 1995 inclusive. The number of general anesthetics and deep sedations administered annually by qualified in dental offices was calculated by surveying all oral and maxillofacial surgeons and dental anesthetists in Ontario in 1990 and 1995. The results provided an estimate of 2,830,000 cases from 1973 to 1995 inclusive. Over this time period there were four deaths associated with cases in which either an oral and maxillofacial surgeon or dental anesthetist administered the general anesthetic or deep sedation, yielding a mortality rate of 1.4 per 1,000,000. This mortality incidence is similar to rates already published for outpatient dentistry.