BACKGROUND Ketamine is an anesthetic drug that is importantly analgesic without respiratory depression. Ketamine increases blood pressure and heart rate. Propofol is an anesthetic drug with good sedation, rapid recovery, but it causes respiratory depression, low heart rate and low blood pressure. Combination of Ketamine and Propofol provides sedation, analgesia and rapid recovery with hemodynamic stability and minimal respiratory depression. The aim of this study was to compare two different combinations of these two drugs to reach necessary sedation scale for the Lp or BMA in pediatric with ALL. METHODS This randomized, double blinded study was designed to compare the quality of sedation and side effects of intravenous Ketofol on 60 patients of both gender. Patients received titrated injection of a solution containing combination of one part of Ketamine and two parts of Propofol (1:2) (group I) or one part of Ketamine and three parts of Propofol (1:3) (group II) to reach almost near 5 sedation level (using Ramsay Sedation Scale). Respiratory and hemodynamic profiles, amount of drug injected and side effects were recorded. RESULTS These drug combinations were used on 60 children with a median age of 6.2 years. In this study, recovery time and hallucination was significantly high in group I, but in both groups hemodynamic were stable, amnesia was enough, and there was no respiratory depression. CONCLUSIONS Lower doses of Ketamine in these combinations have lower psycho mimetic side effects, and shorter recovery time.