Among the elective Surgeries performed at Hanyang University Hospital from March to July 1986, 150 cases were studied. Each 50 cases were given diazepam, lorazepam and mep-eridine as prefnedicants. In the diazepam and lorageparm group, each 25 cases were given by intramuscvlary and intravenously. 40 minutes after injection, scoring the degree of sedation was performed. Scoring the degree of sedation was adopted by "Simple Scoring System" (Nisbet and Norria, 1963). The results were as follows : 1) Comparison of diazepam, lorazepam and meperidine intramusclar administration, sign-ificantly lower souring wan defined in meperidine. (p<0.05 7r riait analysis) 2) Comparison of scoring in intramuscular and intravenous administration of diagepam and lorazepam, no significance were defined in both groups. (p>0.05 by ridit analrsis in both groups) 3) Environmental factors (sex, grade of education, religion and sits of operation) were not influenced on scoring significantly. (p>0.05 by Chi-square test)