Introduction: Spinal anaesthesia in the paediatric population is a safe and reliable method of anaesthesia for infraumbilical surgical procedures. As there is greater variation in intrathecal dosing using a conventional weight-based schedule, a prospective cohort study was designed to administer an age-based intrathecal dosing schedule using 0.5% hyperbaric bupivacaine for infraumbilical surgeries in paediatric patients. Aim: To find the efficacy of this age-based intrathecal dosing in terms of level of sensory blockade, success rate and adequacy of blockade for infraumbilical surgery. Materials and Methods: One hundred and thirty paediatric patients, aged between 2-12 years, posted for elective infraumbilical surgeries were given spinal anaesthesia at a dose of Age/5 (Partha formula) using 0.5% hyperbaric bupivacaine. Sedation during the procedure was provided using a combination of effective doses of pentazocine, midazolam, and atropine. The number of attempts, the success rate, the level of sensory blockade, the duration of anaesthesia and cardio-respiratory complications if any were noted. Results: The mean age of the children was 8 +/- 2.55 years. The mean dose of 0.5% hyperbaric bupivacaine used in this study was 8 +/- 2.55 milligrams. The desired sensory level of T10 was achieved in the first attempt in all the cases (100%) within 10 minutes of the subarachnoid block. The mean duration of anaesthesia was 73.42 +/- 18.6 minutes. In all the patients, the surgical procedures were completed within this anaesthetic time and none of the cases had any conversion to general anaesthesia. No complications were found in any of the patients. Conclusion: Administration of intrathecal dosing of 0.5% hyperbaric bupivacaine using Partha formula (Age/5) is a safe and successful method to provide subarachnoid blockade for infraumbilical surgeries in the Indian paediatric population.