Successive petroleum ether, ethyl acetate and methanol extracts of the whole plant of Amaranthus spinosus Linn. were investigated for the analgesic activity. Experiments were carried out with these extracts for their peripheral and central antinociceptive potentials on acetic acid induced writhing and radiant heat tail-flick models in mice, respectively. In both the models, methanolic extract showed significant writhing inhibition as well as the elongation of tail-flick time at a dose of 500 mg/kg body weight. A linear dose response relationship was also observed.