Abstract: The present study was carried out to assess the antitumor effect of venom from snake, Hydrophis spiralis on the Ehrlich Ascites Carcinoma (EAC). Four groups of albino Swiss mice were treated with three doses of the sub lethal dose of venom, viz., 0.418, 4.18 and 6.27 μg kg-1 body weight (intraperitoneal injection) along with the standard drug 5 flurouracil (20 mg kg-1 b.w.). The biochemical analysis and rest was left to calculate the mean survival time. In EAC bearing mice, mean life span tumor volume, hemoglobin, red blood cell and lymphocytes were significantly decreased when compared to the normal animals. Whereas, body weight, neutrophils and viable tumor cell count was increased in the EAC bearing mice. These changes were brought back to near normal levels in different treatment groups. The macromolecule concentration of peritoneal cells, such as, DNA, RNA and protein, were altered in the EAC bearing mice and observed to be near normal in the treatment groups. The caspase 3 activity was significantly increased in the peritoneal cells of the treatment groups when compared to the EAC bearing mice. The role of apoptotic cascade in EAC cell death was confirmed by the DNA fragmentation on agarose gel. Apart from the antitumor effect, snake venom reduced the tumor burden on the liver and altered the changes in the activities of alanine transaminase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP). Hence the venom from H. spiralis has a potential antitumor effect on the EAC bearing mice.