Plaster models and lateral skull radiographs of 26 orthodontically treated deep overbite cases were analysed before and after treatment and 5–9 years out of rentention. The mean age at the follow-up examination was approximately 22 years. The desired incisor relationship was achieved in the long term in 24 of the cases. The effect of several factors, reported in the literature to be important in the stability of treated deep overbite, was assessed. A considerable range of variation in the behaviour or influence of these factors was found. No marked difference was observed in the long term effects of treatment on the incisor occlusion in the 19 Class 2 Division 1 and the 7 Class 2 Division 2 cases in the sample.