Aims Our objective is to demonstrate the advantages of a full-face CPAP mask using a 3D-printed mould of a child’s face with craniofacial anomalies. The information obtained from the use of this mask will provide us with more insight into the application of 3D technology in OSA. Case Our patient is an 8-year-old female with Pallister Killian syndrome with moderate to severe OSA. She has a collapsed left nasal ala and asymmetrical cheeks. Her sleep quality is suboptimal despite surgery. She has failed multiple types of conventional CPAP masks that result in poor seal and pressure areas. We propose that a customized full face CPAP mask allows optimal comfort and prevents oral leakage. To our knowledge, this is the first application of a full-face CPAP mask created using 3D technology in a paediatric patient with craniofacial abnormalities in Australia. Methodology A 3D scan of the patient’s face was acquired using the Artec Spider handheld 3D scanner. The data was exported and subsequently imported into Geomagic Freeform Plus to design the mould. The patient’s sleep quality was assessed using sleep studies, CPAP machine reports and questionnaires that are completed by the parents immediately after CPAP use and after 12 months of use. Results Previous sleep study suggested at least moderate OSA with REM sleep respiratory disturbance index of 50.7/hour. Her obstructive apnoea-hypopnoea index (OAHI) was 5.1/hour which remarkably reduced to 1.7/hour following use of the new mask with minimal leak. The OSA-18 score reduced from 60 to 56 and the PSQ score improved from 65 to 36 in 12 months. Her parents also report better comfort and less leaks. Conclusion A customized full face CPAP mask developed from a 3D printing has shown to be beneficial in improving adherence, reducing leaks and pressure areas. A larger study involving children with craniofacial abnormalities could be considered following this case study.