In total knee replacement operation, patients have a severe pain in the postoperative period. Because of side effects of opioids, multiple postoperative pain treatment regimens are more suitable in these elderly patients. In this double-blind, randomized, placebo controlled study, the effect of lornoxicam administration (32 mg/48 hour) on morphine consumption and drug-related side effects were investigated in elderly patients undergoing total knee replacement. Group M (n=23) and Group L (n=23) received morphine with patient controlled analgesia (PCA) device postoperatively. Additionally Group L received lornoxicam 16 mg intravenously 15 minutes before surgery and 8 mg at postoperative 12th and 24th hours. Morphine consumption in Group L were significantly lower than in Group M at 2, 3, 6, 8, 24, 36 and 48th postoperative hours (p<0.05). At the end of 48th hour mean total morphine consumptions (mean+/-SD) for Group M and Group L were 63.70+/-15.70 mg and 34.60+/-16.32 mg, respectively. AUC (area under the curve) Morphine 0-48h in Group M was 59+/-13 and in Group L it was 30+/-13 (p<0.001). Incidence of side effects in Group M were 60% and 25% in Group L (p<0.05). In Group M, 8 patients (40%) experienced nausea and 3 (15%) patients experienced itching where as in Group L, 3 patients (15%) experienced nausea, 1 patient (5%) itching, 1 patient (5%) dry mouth. Lornoxicam administration in total knee replacement is associated with decreased morphine consumption for postoperative analgesia and fewer side effects.