This prospective randomized study compared I.V. infusion of tramadol "T" with fentanyl "F" for analgesia and postoperative outcome in 30 patients undergoing major abdominal surgery. A balanced general anaesthetic technique was given to both groups. In "T" group (n=15), tramadol (1mg.kg-1) was given firstly then infusion started as follow: 1st hr: 1mg.kg-1.hr-1, 2nd hr.: 0.75 mg.kg-1.hr-1 and 0.5 mg.kg-1-hr"! for the following hours. In "F" group (n=15), Fentanyl (1.5 ng/kg-1) was given firstly then infusion was given in the following regimen: 1st hr: 1jig.kg-1.hr1, 2nd hr.: 0.75 u.kg--1hr-1 and 0.5 ug.kg-1,.hr-1 for the following hours. Infusion stopped at time of closure in both groups. No significant haemodynamic differences were detected between both groups. The early postoperative gascmetric readings
were within acceptable values in both groups. Mean VPS ranged from 0.47 ± 0.9 to 1.2 ± 0.4 and from 0.73 ± 0.3 to 1.33 ± 0.5 in "T" and "F" groups respectively in the first 6 hours posto-peratively. VPS showed no significant differences between both groups. It increased significantly as related to basal value after 5 and 4 hours in "T" and "F" groups respectively. We concluded that tramadol given by I.V. infusion appears to be a promising analgesic with respiratory and haemodynamic stability.