Objective : To evaluate the importance of dental status for long-term outcome after alveolar bone grafting in patients with unilateral cleft lip and palate. Design : Retrospective longitudinal study. Setting : Cleft lip and palate-craniofacial center, Uppsala University Hospital, Sweden. Patients : A total of 67 consecutive patients with unilateral complete cleft lip and palate. Interventions : Secondary alveolar bone grafting, prior to the eruption of the permanent canine, was performed at the average age of 10.0 years (range, 8.5 to 12.0 years). Main Outcome Measures : Alveolar bone height was evaluated with the modified Bergland index at 1 and 10 years after surgery. Results : Of the patients, 97% had modified Bergland index grade I and the remaining 3% had modified Bergland index grade II at 1 year after surgery. At 10 years' follow-up, 43% showed modified Bergland index grade I; 55%, modified Bergland index grade II; and 2% (one patient), modified Bergland index grade III. The degree of dental anomalies in the cleft area, such as enamel hypoplasia, incisor rotation, incisor inclination, canine inclination, and oral hygiene registered preoperatively, all correlated negatively to the modified Bergland index at 10 years after surgery. Enamel hypoplasia (ρ = 0.70195, P < .0001), followed by canine inclination (ρ = 0.55429, P < .0001), showed the strongest correlation to reduced bone height in the cleft area. Conclusions : In patients with unilateral cleft lip and palate, excellent results from secondary alveolar bone grafting in terms of bone height in the alveolar cleft tend to decrease with time. This seems to be correlated with factors that might to some extent be treated preoperatively through adequate planning and execution of the orthodontic treatment.