AIM To evaluate the success rate of Class II malocclusion treatment with functional appliances 6-7 years after treatment. SUBJECTS AND METHODS The patient records of all listed young adults between 18-20 years (n=1054) treated in a general practice in Eslöv, in southern Sweden were reviewed, for the purpose of finding patients treated with removable functional appliances (Andresen- and van Beek activators). From 61 subjects that previously had been treated with these appliances fifty-four patients, (34 boys and 20 girls) accepted to participate in the study. The test group was matched, in terms of sex and age, with an orthodontically untreated group of 35 boys and 21 girls. All participants were examined clinically and study casts were taken to evaluate the occlusion, lip closure, gingival impingement, and forced bite. Weighted PAR (wPAR) was calculated. Successful treatment was defined if at least three of the following criteria were met: - Normal sagittal molar relation (± ½ cusp) - Overjet less than 5 mm or being reduced by at least 50 % - No gingival impingement - Competent lip closure. If retreatment with fixed appliances was needed or if the treatment had been interrupted prematurely, because of lack of cooperation or undesired treatment result, the treatment was considered as unsuccessful. RESULTS Twenty patients (37,0 %) succeeded with the functional appliance treatment. Twenty-four patients (44.4 %) interrupted the treatment with the functional appliance prematurely, mainly due to lack of cooperation. Fifteen patients (27.8 %) received treatment with fixed appliance in additional to the functional appliance. Very few patients showed gingival impingement and forced bite in both treated and control group. Significantly more patients in the functional appliance group (35.9%) had incompetent lip closure compared with the fixed appliance group (13.3%) and the control group (3.6%). The patient group treated with functional appliance only, had the significantly highest wPAR (mean=18.19). Including only those patients that fulfilled the functional appliance treatment, wPAR declined to 13.78. The patient group who had received additional treatment with fixed appliance showed a mean of 8.67 in wPAR. The control group showed a mean wPAR of 7.43. CONCLUSION Treatments with functional appliances in a general practice, shows that the failure rate is rather high, mainly due to cooperation problems. It is therefore of importance, already before starting treatment, to estimate the child’s cooperation ability and to avoid treatment with removable appliances, if the child or parents are reluctant about such treatment.