Background and Aims:Thoracic paravertebral block (TPVB) provides effective analgesia in breast surgery. Recently, use of erector spinae plane block (ESPB) in controlling post-operative pain has proved effective. This study aimed to compare the effect of ESPB with TPVB in post-mastectomy acute pain control.Methods:A prospective, randomised double-blinded study enrolled 70 adult female patients, scheduled for modified radical mastectomy. Patients were randomised into two groups, receiving 20 ml of 0.25% bupivacaine: group I (TPVB) and group II (ESPB). Post-operative 24 h morphine consumption, intra-operative fentanyl consumption, time of the first request for analgesia and post-operative visual analogue scale (VAS), heart rate (HR), mean blood pressure (MBP) and complications were recorded.Results:Post-operative 24 h morphine consumption and time of the first request for analgesia were comparable between both groups (P = 0.32 and 0.075, respectively). There was no significant difference in the intra-operative fentanyl consumption. There was also no significant difference in VAS between both groups over the 24 h of study. Four patients in group I developed pneumothorax with no significant differences between both groups (P = 0.114). Incidence of nausea and vomiting was comparable between both groups. All patients displayed a stable haemodynamic profile.Conclusion:Both TPVB and ESPB can be effectively used in controlling post-mastectomy pain and reduce intra-operative and post-operative opioid consumption.