A survey was mailed to a stratified random sample of general dentists to determine the amount and nature of orthodontic treatment provided by general practitioners to their patients. The response to the survey was 75%, a rate considered excellent for this type of mailing. A large majority of the responding dentists (76.3%) provide orthodontic services to their patients, with 19.3% providing comprehensive orthodontic treatment. The percentage of time spent providing orthodontic services varied greatly among general dentists, with only a very few practitioners spending more than 50%. The number of patients under active treatment also varied widely, with only about 17% of those practitioners providing comprehensive treatment having more than 50 patients. A comparison of the three groups of practitioners showed that there was no relationship between the level of orthodontic involvement (none, limited, comprehensive) and the number of miles from orthodontic specialist or the pattern of referrals to orthodontists. Extrapolation of data from this study to the results of other investigations led to an estimate of the relative percentage of treatment provided by orthodontic specialists, pediatric dentists, and general practitioners. Almost two thirds of orthodontic patients are treated by orthodontic specialists, with pediatric dentists treating less than 4%. Slightly less than one third of all orthodontic patients appear to receive treatment from general practitioners.