Objectives: This study is aimed at testing the efficacy of ultra sound guided erector spinae plane block (ESPB) with 20ml of 0.2% ropivacainein providing postoperative analgesia in patients undergoing breast surgery. Materials and Methods: After seeking approval from the hospital ethics committee and obtaining written informed consent from participants, this single blinded prospective randomised control study was conducted on 60 patients posted for breast surgery under general anaesthesia. The recruited participants were randomly assigned into two equal groups B and C by closed envelope technique.Group B patients were given ultrasound-guided ESPB with 20 ml of 0.2% ropivacaine and Group C patients were given routine postoperative port site infiltration with 20 ml of 0.2% ropivacaine. Postoperative pain and need for rescue analgesics were noted. Chi-square test, independent sample t test, Mann Whitney U test was used for statistical analysis. Results: Pain score was lower in Group B patients up to 12h (P<0.007). At 24h the pain scores between the two groups were comparable. The rescue analgesic requirement was also significantly less in group B compared to Group C (23.3% vs. 70%), and this difference was statistically significant (P=0.01). On comparing the incidence of postoperative nausea and vomiting, there was no significant difference between the two groups. No adverse events were noted in both groups. Conclusion: Ultrasound-guided ESPB with 20ml of 0.2% ropivacaine is superior to local infiltration in providing postoperative analgesia in patients undergoing breast surgery. It also decreases postoperative tramadol requirement.