Objectives: Infra orbital nerve block is utilized for postoperative pain control in children undergoing cleft lip repair. This study was conducted to compare the effectiveness, advantages and disadvantages of bilateral infra orbital nerve block using ropivacaine combination with dexamethasone and dezocine for postoperative pain relief and stress level following cheiloplasty. Methods: Sixty paediatric patients aged 1～6 years undergoing cheiloplasty were selected by simple random sampling and were divided into two groups. All the children received standardized premedication with midazolam and penehyclidine hydrochloride, were operated upon under general anaesthesia and the block was performed at the end of surgery before reversal. Group A patients were administered bilateral infra orbital nerve block with 0.25% Ropivacaine 1 ml and 1 mg dexamethasone amount to 2 ml. Group B patients received dezocine 0.1 mg / kg IV. Postoperatively, postoperative agitation，CRIES scores at 2，4，6，8，12，24h after surgery and adverse reaction were recorded as well. Need for supplementary analgesics and duration between the administration of block/ dezocine and the total dose of supplementary analgesics within 24 hours were noted. Side effects such as nausea and vomiting, respiratory depression and cyanosis during each of these periods were noted. In order to detect plasma 1eve1 of cortisol(COR), norepinephrine(NE), epinephrine(E) before anaesthesia(T1), at the end of surgery before reversal(T2) and 8h(T3)，24h(T4) after surgery. Results: Both the groups were comparable for age, sex, weight and operative time with no statistical difference. The incidence and the score of agitation were lower in group A than in group B. At 4h～12h each time point, group A patients had lower CRIES scores than group B(p<0.001). However, at 2 hours, 24 hours, there was no difference in the scores. No patient in both groups required supplementary analgesics by the 2st hour. However, At the 4th and 6th hour, in Group A, 3.33% and 10% of patients had pain score ≥ 4 while in group B, the patients with pain score ≥4 increased from 6.7 % at 4th hour to 30% at 6th hour. At the 8th hour, 16.67% of children in group A had pain score ≥ 4 in comparison to 76.67% in group B and this difference was highly significant (p<0.001). By 12th and 24th hour, however, the number of patients with pain score ≥ 4 was almost comparable in both the groups. Group A had lower total amounts of supplementary analgesics than group B. The mean duration of analgesia in group A was 715± 32.12 minutes. In comparison, the mean duration of analgesia in Group B was 263 ± 22.4 minutes which was highly significant statistically (p<0.001). Only one patient had nausea and vomiting in group A compared to 5 (16.67%) in Group B. There was no incidence of respiratory depression or cyanosis in any of the groups. A similar ascent trend of plasma concentration of cortisol(COR), norepinephrine(NE), epinephrine(E) at the end of surgery compared with before anaesthesia in both groups. At 8th hour, the plasma concentration of COR, NE, E increased significantly compared with before anaesthesia (p<0.05).Group A had lower concentration of COR, NE, E at 8th hour. Conclusion: The results indicate that bilateral infra orbital nerve block using ropivacaine combination with dexamethasone provides effective analgesia in the postoperative period, lasting for 12 hours in comparison to 4½ hours following the administration of intravenous dezocine, with no major untoward effects. Moreover, this analgesia method attenuated effectively stress response caused by pain discomfort.