Objective: To provide scientific validation for the antipyretic activities of Amaranthus viridis (Linn.), Amaranthus caudatus (Linn.) and Amaranthus spinosus (Linn.). Methods: The antipyretic activity of methanol extracts of all three plants at doses of 200 and 400 mg/kg was investigated by yeast induced pyrexia in rats. Paracetamol (150 mg/kg, p.o.) was used as reference drug and control group received distilled water. Rectal temperatures of all the rats were recorded and compared at 19 h, immediately before extract or vehicle or paracetamol administration, and again at 1 h interval up to 24 h by thermal probe Eliab themistor thermometer. Results: At 400 mg/kg dose all the three methanolic extracts showed significant (P<0.01) reduction in yeast provoked elevated temperature as compared with that of standard drug paracetamol, whereas 200 mg/kg dose is less effective when compared with higher dose (P<0.05). Conclusions: The results show that methanol extract of three plants of Amaranthus possesses a significant antipyretic effect in maintaining reducing yeast-induced elevated body temperature in rats and their effects were comparable to that of the standard antipyretic drug paracetamol.