Introduction: Spinal anesthesia is the most commonly used technique for lower abdominal surgeries postoperative pain control is a major problem because spinal anesthesia using only local anesthetics is associated with relatively short duration of action, and thus early analgesic intervention is needed in the postoperative period. Short acting spinal anaesthesia may help to prevent complications associated with delayed immobilization. Objective: To examine whether adding intrathecal Fentanyl to bupivacaine intensify sensory and motor block without prolonging recovery time for urosurgeries. Materials and Methods: A prospective observational study was contact at dept. of Anaesthesia, Shaheed Tajuddin Ahmad Medical College Hospital, Gazipur, Bangladesh from March to August 2021. Seventy five (75) patients included in our study. American Society of Anaesthesiologists physical status I and II scheduled for elective urological procedures were studied in a double-blinded, randomized prospective manner. Random allocation was done as, Group A (n=25) receiving intrathecal bupivacaine 12.5 mg; Group B (n=25) bupivacaine 10 mg with 25 μg of fentanyl; and Group C (n=25), bupivacaine 5 mg with 25 μg of fentanyl. Assessment of sensory, motor block and duration of sensory analgesia was done. Results: In our study the demographic data were comparable in all the three groups. The time for two segment regression was statistically significant between all three groups (p<0.001). The mean time for two segment regressions for group A was 104.8 minutes whereas for group B mean time was 161.8 min and for group C mean time was 80.37 minutes. It was longest for group B and shortest for group C. The total duration of motor block was compared among the three groups after initiation of the SAB. There was statistically significant difference regarding total duration of motor block, time for two segment regression and duration of sensory analgesia between each pair of groups. The duration of motor