No doubt that Post arthroscopic pain has a negative impact on the patient's psychology causing discomfort and prohibiting early mobilization. Seventy five patients aged between 18-60 years and ASA I-II physical status were scheduled for a routine elective knee arthroscopy for anterior cruciate ligament (ACL) repair. Standard general anesthesia was given to all patients. The patients were randomized in double-blind manner into five equal groups according to the intraarticular drug injected. Group ketamine received 1 mg·kg–1 ketamine, group Clonidine received 1 µg kg–1 clonidine, group Neostigmine received neostigmine 500 µg, group Magnesium received 500 mg of 10% magnesium sulphate (MgSO4) and group Control received 20 ml of 0.9% normal saline. The volume of injectate was standardized at 20 mL.