Introduction: Appropriate size selection of ProSeal laryngeal mask airway (PLMA) is an important prerequisite for successful use of the device. Size of PLMA is often selected based on weight of patients. We aimed to determine whether combined width of patient's index, middle and ring fingers could be used as an alternative to weight-based selection of appropriate size of PLMA. Materials and methods: In this prospective randomized study, 102 patients aged 6 months to 10 years were included. Patients were allocated to one of two groups based on a randomization table and PLMA inserted according to the group allocated. In Group S, PLMA size selected according to weight-based method whereas in Group N, PLMA size was selected based on 3-finger breadth of patients. We recorded insertion parameters, fiberoptic scoring of glottic visualisation, airway manipulations and postoperative complications. Results: In 68 children (66.66%) size of PLMA was same according to both methods. The kappa coefficient was 0.461 concluding moderate agreement between two methods. In the remaining 34 children (33.34%), the disagreement in sizes were with only one size, in whom the patient's weights were borderline values. The PLMA insertion time, ease of insertion, insertion attempts, fiberoptic view of position of device were comparable in both groups. There were no significant complications in the postoperative period. Conclusion: Three finger breadth sizing method can be used as a good alternative to weightbased method for selecting appropriate size of PLMA in children.