Whilst a double lumen tube (DLT) is the gold standard for one lung ventilation, its double curvatures and increased diameter can make intubation difficult, potentially compounded by a challenging airway. We describe the successful placement of DLT in a difficult airway, and confirmation of the appropriate placement of DLT by using flexible paediatric video-ureteroscope (digital Olympus URF-V2/V2R), without which the purpose of achieving lung isolation was not possible.