Thoracotomy incision is the most painful surgical incision which causes reduction in FRC and ability to take deep breath and cough out sputum . This results retention of secretions, atelectasis and finally pneumonia.In lateral thoracotomy incision, there is intercostal nerve disruption,pleura and chest wall inflammation which contribute to pain and discomfort. Eventhough thoracic epidural technique is the gold standard for pain relief in thoracotomy surgeries,  thoracic paravertebral block has numerous advantages over thoracic epidural as it provides adequate unilateral pain relief with cardiovascular stability.So, this study has been conducted to compare the analgesic efficacy of continuous infusion versus intermittent bolus of bupivacaine in thoracic Paravertebral block for elective thoracotomy surgeries where we have found that continuous infusion of Local Anaesthetic in the paravertebral space provides continuous pain relief with absence of break through pain and better patient compliance to postoperative physiotherapy and ability to cough out sputum.