PURPOSE: In order to determine the differences in speech outcome based on timing of operation in submucous cleft palate, we have reviewed our experiences in the Furlow palatoplasty over the last 11 years. METHODS: From March 1996 to March 2006, 38 submucous cleft palate patients received Furlow palatoplasty. 10 developmentally delayed patients were excluded and 5 patients were lost to follow up. The rest 23 patients were reviewed. Speech was evaluated preoperatively and postoperatively, and speech therapy was performed accordingly. Perceptual speech assessment included hypernasality, nasal emission and articulation disorder. Cinefluorography was performed to aid perceptual assessment. Based on timing of operation, the patients were divided into 3 groups as following: Group A under 24 months(8 patients), Group B from 25 to 48 months(6 patients), and Group C over 49 months (9 patients). Except 1 patient under speech therapy yet, resultant speech was compared. RESULTS: The rate of abnormal speech was higher in Group C(3/9, 33.3%) than in Group A(0%) or B(0%). All 3 patients who had been discontinued of speech therapy from the parent's judgment had abnormal speech. The reason for the discontinuation was that the regular speech therapy was a burden at school age. Any patients who had continued speech therapy had normal speech. CONCLUSION: The results of our study shows that operative timing is associated with speech development. Maintenance of speech therapy was an important factor for normal speech development. It will be helpful to perform a palatoplasty before 48 months of age to complete speech therapy before the school age.