Background: it's considered that post-operative pain management in children is essential as it reduce the pain as well as anxiety of the parents regarding post-operative pain. There are some options which are found and being used currently by pediatric anesthetists. However there is no consensus over a single best method. Post- operative pain management had always been a major concern of parents as well as pediatric anesthetists. Contrary to the ancient notion that children don't feel pain, many studies have focused on the importance of good pain management in children. According to the studies, children in surgical ward feel more pain than children in medical ward and prevalence was found to be 44% and 13% respectively and it was found that about 64% of pediatric patients after surgery experience moderate to severe pain while 29% experience mild pain. Objectives: the aim of this study was to compare pain scores in patients undergoing inguinal herniotomy after caudal block and intravenous nalbuphine. Patients and Methods: this comparative double blind study was conducted at Paediatric Surgery Department. We included patients with age range of 3-12 years. The children were randomly divided into two groups. Group C included Caudal Block; and Group N included patients who received Nalbuphine. In group C patients, after herniotomy and before extubating the patient, caudal block was introduced by giving Bupivacaine 0.25% according to body weight. In patients in group N, immediately after herniotomy, nalbuphine was given intravenously 0.18 mg/kg according to body weight. Patients were shifted to post-operative ICU where pain scores were measured at 0,1,2,4 and 8 hours. Also any side effect of the drugs was noted and taken care of. For pain measurement Faces Pain scale was used. If any patient developed pain score 8 or more, patient was given paracetamol10 mg/kg. Results: we have used FACES pain scale in our study which is a verified scale for pain assessment in children with the age range of 3-12 years. There was no significant difference between the two study groups as regard side effects, as 14.8% of group 2 (Caudal Group) cases had side effects compared to 3.6% for group 1 (Nalbuphine cases(p=0.052). As regard the need for rescue analgesia, no significant difference was found between the two study groups. Regarding our study, there was no significant difference between the two study groups as regard pain scale at 1 hour. However, a highly significant difference was found between the two study groups as regard pain score at 2, 4, and 8 hours with higher pain among caudal block group. Conclusion: nalbuphine is better than caudal block for post-operative pain management after inguinal herniotomy in children.