Acute postoperative pain due to insufficient pain control is a major risk factor for development of chronic pain after breast surgery. Regional anaesthesia is considered protective for cancer recurrence by its direct and indirect anti proliferative effects. Use of these techniques is associated with better pain control , decreased opioid consumption and their side effects. Paravertebral block is a established regional anaesthesia and analgesia technique for breast cancer surgeries.However erector spinae plane block is a novel interfacial block technique which can be a viable alternative to paravertebral block due to its fast , easy and safe execution . There are numerous studies on paravertebral block but there is a very limited literature on erector spinae plane block in breast surgeries and there is no study comparing paravertebral block with erector spinae plane block in breast surgeries.Thus we are performing this randomized controlled trial to compare the efficacy of paravertebral block with erector spinae plane block in breast surgeries in total 80 patients ( 40 in each group). In Group P , ultrasound guided paravertebral block will be given at T4 level with 20 ml of 0.5 % Ropivacaine and in Group E , ultrasound guided erector spinae plane block will be given at T5 level with 20 ml of 0.5 % Ropivacaine. After giving the block , GA will be given.Any block related complications will be noted. In postoperative period the efficacy of both the blocks will be compared in terms of duration of postoperative analgesia (time to first rescue analgesic ) , total number of rescue analgesics required and patient satisfaction .