Introduction: Local anaesthetic like bupivacaine is commonly used in spinal anaesthesia, but the duration of spinal anaesthesia may be short and limited, and higher doses of rescue analgesics may be required in the postoperative period. This can be avoided by using higher doses of bupivacaine which again can produce cardiac toxicity. Studies have shown that duration of analgesia due to bupivacaine in spinal anaesthesia can be prolonged by using adjuvants such as midazolam, opioids, neostigmine, dexmedetomidine, and clonidine. Almost all opioids have been used as adjuvants intrathecally. Material and methods: This randomized controlled study was carried out over a period of 6 months, after obtaining approval from the Hospital Ethics Committee and written informed consent from the patients. Ninety-nine patients of Anaesthesiologists Classes I or II of either sex and of age 25-60 years, posted for lower abdominal surgery were randomly divided into 3 groups (n = 33) using computer-generated program. Assigned random group was enclosed in a sealed envelope to ensure concealment of allocation sequence. The anaesthesiologist, who was not involved in the study, opened the envelope in operation theatre and prepared the drug accordingly. The observation was done by the anaesthesiologist who was blinded to the drug. Patients having severe systemic disorders such as diabetes mellitus, hypertension, heart disease, allergy to bupivacaine, spine deformity, increased intracranial pressure, neurological disorders, haemorrhagic diathesis, and infection at the puncture site were excluded from the study. Result: A total of 106 patients initially enrolled in this study, 7 patients had to be excluded because of logistical reasons or other violations of the study protocol. Ninety patients were included and randomly assigned to their treatment groups. Conclusion: Intrathecal clonidine (75 μg) when added to bupivacaine in spinal anaesthesia provides prolonged duration of postoperative analgesia than 25 μg of fentanyl but with higher degree of sedation. Fentanyl (25 μg) may be recommended as a better option when sedation is not desirable. We concluded that intrathecal clonidine 75 𝜇g with bupivacaine prolonged intraoperative anaesthesia and the time to first analgesic request compared to fentanyl, however, the total analgesic consumption in the first 24 h postoperative was similar in fentanyl and clonidine groups following elective lower abdominal surgeries.