Gender determination from unidentified human remains is an important procedure in forensic medico–legal investigations. Sinus radiographs can be used for the identification of gender. The aim of the present study was to determine gender using maxillary sinus index from lateral cephalograms and also to evaluate the reliability of this technique. Methodology: 100 digital lateral cephalograms (50 males and 50 females) were obtained from previous data of patients with age ranging between 20–50 years. The width, height and maxillary sinus index were calculated and gender was determined using discriminant function analysis. Results: The mean maxillary sinus height, width and index were greater among males than females and the accuracy of maxillary sinus measurements to identify males was 84.0% and females was 74.0%. Conclusion: The morphometric analysis of maxillary sinus can be used as a reliable tool in gender determination.