Postoperative pain is a complaint that must be effectively managed. Various analgetic methods are implemented to alleviate open cardiac surgery for postoperative pain, but none of the methods is ideal for managing postoperative pain. Erector spinae plane block is a new technique in open cardiac surgery for postoperative pain. This study aims to determine the difference in post-open cardiac surgery pain measured by using the VAS pain scale in patients with erector spinae plane block and parasternal block. The study was conducted in June-November 2021 in Hasan Sadikin General Hospital, Bandung. This was a single-blind control trial in thirty patients. Patients were divided into two groups, a parasternal block group (group A, n=15) and an erector spinae plane block group (group B, n=15). Postoperative pain was measured by using the VAS pain scale on hours 0-1, 1-6, 6-12, and 12-24. Numerical data were analyzed by using the unpaired T-test and the Mann-Whitney test. Categorical data used the Chi-Square test. ESP blockade has higher effectiveness than a parasternal block in managing pain after open cardiac surgery.