Background: Obstructive sleep apnoea syndrome (OSAS) shows a strong association with obesity. However, OSAS is also associated with craniofacial deformities irrespective of body weight, particularly in the young. Surgery represents the best therapeutic option for OSAS patient with craniofacial deformities. This study was undertaken to evaluate OSAS caused by craniofacial deformities and to study the effect of surgical correction in these cases. Methods: Thirty one patients with symptoms of OSAS and craniofacial deformity who attended our outpatient department or were referred for pre-operative evaluation prior to corrective surgery were included in this retrospective study. Details of demography, history and clinical examination were obtained. Polysomnography (PSG) performed was level III (cardio-respiratory or limited channel study). The diagnostic criteria were symptoms suggestive of sleep apnoea and apnoea hypopnoea index (AHI) of > 1 in children and > 5 in adults. Surgical treatment consisted of release of the temporo-mandibular joint (TMJ) ankylosis, mandibular distraction osteosis (DO) and maxillomandibular advancement (MMA) either alone or a combination of surgeries. Patients were reassessed with repeat PSG to document improvement post intervention. Those patients who did not show improvement with surgery alone were treated with CPAP therapy. CPAP therapy was advised in cases that refused surgery. One case of retrognathia was treated with oral prosthesis. Results: Of the 31 cases were included in this study, age range from 6-27 years, the mean age was 15.10 years and 17 (54.8%) were males while 14 (45.2%) were females. The mean body mass index (BMI) was 16.72 kg/m². Snoring and excessive day time sleepiness (EDS) were the predominant symptoms in 27 (87.1%) and 20 (64.5%) cases respectively. The other symptoms included choking during sleep in 16 (51.6%), scholastic backwardness in 15 (48.4%) irritability in 14 (45.2%), non refreshing sleep in 13 (41.9%), enuresis in 12 (38.7%) and early morning headaches in 11 (35.5%) cases. In most cases symptoms were present since early childhood. The predominant craniofacial deformity associated with OSAS in this study group was bilateral TMJ ankylosis with micrognathia/ retrognathia.in 14 (41.9%) and unilateral TMJ ankylosis with micrognathia/ retrognathia in 8 (25.8%). Other deformities were retrognathia 4 (12.9%) and micrognathia 2(6.5%). Surgery was performed in 25 (80.6%) cases, 5 (16.1%) refused surgery and opted for CPAP and 1 (3.2%) case was treated with oral prosthesis. Symptoms improved significantly in 96.8% of the patients following surgery. Conclusion: OSAS with craniofacial deformity is caused by compromised upper airway space. Bilateral or unilateral ankylosis with retrognathia/ micrognathia of TMJ is the most common craniofacial deformity causing OSAS in the young. Syndromic associations of craniofacial deformities also cause OSAS. Surgical methods TMJ ankylosis release, mandibular DO and MMA, either alone or in combination show good success rate. The consequences of untreated OSAS in the young are neuro cognitive disorders and cardiac consequences seen later in life. Hence it is important to recognize and treat OSAS associated with craniofacial deformities as early as possible to avoid these consequences.