Heparin was extracted from marine gastropod T. attenuata through the sequential precipitation with methanol and ethanol. The metachromatic dye method using toluidine blue was used to estimate colorimetrically the amount of heparin present in the sample. The anticoagulant activity of the sample was calculated as per United States of Pharmacopoeia standard procedure using sheep blood. After the purification, samples were analyzed, for the presence of heparin, with agarose-gel electrophoresis and HPLC and the mobility of the sample and the peak respectively were compared with standard heparin. The results of the present study shall help in finding out alternate source.