Drugs commonly used in modern medicine for suppression of pain and fever provide only symptomatic relief and long-term use of these drugs is associated with serious adverse effects. Recently, some evidences suggest that Nigella sativa inhibit eicosanoid generation in leukocytes and lipid peroxidation. They are reported to inhibit both cycloxygenase and 5-lipooxygenase pathways of arachidonic acid metabolism. The present study was aimed to evaluate the analgesic activity of pure compound, thymoquinone the major constituent of Nigella sativa seeds in mice. The analgesic activity was determined by hot plate, tail immersion, tail flick method and acetic acid induced writhing test in mice. Thymoquinone (10, 20, 30 mg/kg, body weight) and Aspirin (20mg/kg) made as suspensions prepared in 1% carboxy methyl cellulose and were fed to mice intraperitoneally. In tail flick method thymoquinone exhibited maximum analgesic effect at a dose of 30mg/kg after 120 min as compared to control and standard. Maximum analgesic effect was noted at a dose of 10 mg/kg after 120 min. the poor analgesic effect of thymoquinone at a dose of (20 and 30 mg/kg) as compared to control and standard drug by hot plate method. However with writhing test the thymoquinone showed maximum protection at a dose of 30 mg/kg (98.23%). The thymoquinone have minimum effect showed at dose of 10 mg/kg (69.72%) and 20 mg/kg (42.26%) as compared to standard and control. But in tail immersion method thymoquinone exhibited maximum activity after 120 min at a dose of 20 mg/kg as compared to control and standard drug while at a dose of 30 mg/kg the compound did not showed any further enhancement in analgesic activity. It is concluded from the present study that thymoquinone the major constituent of Nigella sativa possesses potent analgesic activity in mice. Keywords: Thymoquinone, Nigella sativa, Hot plate, Tail immersion, Tail flick method, Acetic acid induced writhing test