Difficult laryngoscopy is more common in patients with diabetes mellitus due to limited joint mobility. Early identification of difficult airway helps in planning safer anaesthesia. The palm print sign is a simple, non-invasive bedside test that reflects joint stiffness and may predict difficult laryngoscopy. This is a prospective observational comparative study conducted in the Department of Anaesthesiology, SRM Medical College Hospital and Research Centre. Adult diabetic patients scheduled for surgery under general anaesthesia with endotracheal intubation will be included after informed consent. Pre-operative airway assessment will be done using palm print sign, Mallampati classification, thyromental distance and degree of head extension. During induction of anaesthesia, direct laryngoscopy will be performed by an anaesthesiologist blinded to pre-operative assessment, and laryngeal view will be graded using Cormack–Lehane classification as the reference standard. The primary outcome is to assess the diagnostic accuracy of palm print sign in predicting difficult laryngoscopy. Secondary outcomes include comparison with other airway assessment tests and agreement with Cormack–Lehane grading.