Introduction: Post-endodontic pain remains a significant challenge to the dental profession. It has been suggested that calcium hydroxide has pain-preventive properties through its anti-microbial and tissue-altering effects. The aim of this study is to evaluate the effect of intra-canal calcium hydroxide dressing on postoperative pain in female patients diagnosed with symptomatic irreversible pulpitis. Material & Methods: 51 female patients aged 20-40 years, diagnosed with symptomatic irreversible pulpitis were included. Subjects were randomly assigned to calcium hydroxide Group, 26 subjects or dry cotton pellet Group, 25 subjects. Subjects were given anesthesia, rubber dam isolation; access cavity, complete pulp extirpation, working length then canals were instrumented using hand K-files until size# 25. Ca(OH)2 was applied in (Group 1) and dry cotton pellet was put in (Group 2) then access cavities were restored. All subjects were given pain chart to fill after 24 and 48 hours. Results: The mean baseline pain level was severe (3.77 and 3.72) in Group 1 and Group 2 respectively. A significant reduction in the pain level was 1.81 & 1.38 in Group 1 and 2.16 & 1.76 in Group 2 after 24 and 48 hours. A superior pain relive (63.3%) was seen in Ca(OH)2 Group compared to control Group 52.7%. Conclusion: The emergency treatment of choice of symptomatic irreversible pulpitis is complete pulp extirpation. Ca(OH)2 reduced post-endodontic pain more than control Group but not significantly. We recommend using Ca(OH)2 since it did not have any negative influence in post-endodontic pain. Small sample size is a major limitation in our study.