Objective: To compare the incidence of post-operative pain in teeth with symptomatic irreversible pulpitis with and without occlusal reduction. Materials and Methods: This randomized controlled trial was done in the Department of Operative Dentistry Armed Forces Institute of Dentistry (AFID) Rawalpindi from 1st June 2019 to 31st December 2019. A total of 262 patients from 20-50 years of age from both gender presenting with symptomatic irreversible pulpitis in their mandibular 1st Molar were randomly divided into two equal groups of 131 patients with the help of scientific random number table. Endodontic therapy was initiated under rubber dam, following pulpectomy and disinfection with frequent irrigation canals were prepared, intra-canal dressing was placed and the cavity was restored with cavit after which a 2mm occlusal reduction was performed for teeth included in group A and no occlusal reduction was done for Group B. Post-operative pain was recorded at 24 hours, 48 hours and 72 hours using the visual analogue scale. Data was analyzed using SPSS 21. Results: There was no statistical difference in the post-operative pain between the two groups. Conclusion: Occlusal reduction has no significant impact on post-operative pain in teeth with irreversible pulpitis.