Introduction: Spinal anaesthesia is a popular and common technique used worldwide. A newly introduced long acting amide linked local anaesthetic called `ROPIVACAINE, produces less motor blockade and is of shorter duration than bupivacaine. Intrathecal clonidine is being extensively evaluated as an alternative to neuraxial opoids for control of pain and has proven to be a potent analgesic. A very important advantage of ropivacaine over bupivacaine is less cardiovascular toxicity. Aims and objectives: present study was planned to investigate the effects, ( onset of action, duration of action, quality of sensory and motor block, haemodyamic stability and post–operative analgesia ) of intrathecal 4.0 cc of 0.75% isobaric ropivacaine and 3.5 cc of 0.50% isobaric ropivacaine with 30 mcg clonidine plus 0.3 cc of sterile normal saline in benign prostate hyperplasia patients undergoing trans uretheral resection of prostate. Materials and methods: this Prospective, randomized, double blind, comparative study was conducted at the Department of anaesthesiology and Critical Care, Government Medical College and Associated Group of Hospitals, Kota in patients posted for elective trans urethral resection of prostate with benign prostate hyperplasia. We made two groups of cases i.e. Group R (ROPIVACAINE) and Group RC (ROPIVACAINE WITH CLONIDINE). sample size was 80, which was divided into two groups of 40 each. Standard protocol followed to administering spinal anaesthesia. All data were collected and analysed with the help of suitable statistical parameters. Results: Our study results in that combination of clonidine (30 mcg) as an adjuvant with 0.50% isobaric ropivacaine (17.5 mg) in subarachanoid blockade for trans urethral resection of prostate results in prolonged duration of sensory blockade and extended postoperative analgesia compared to plain 0.75% isobaric ropivacaine (30 mg).