Citrus limetta Risso (Rutaceae), commonly known as sweet lime in English and Mousambi in India, has been traditionally used for several medicinal purposes. This study explored the relationship between Citrus limetta fruit peel and its antitumor activity against Ehrlich ascites carcinoma (EAC) bearing mice. The antitumor activity of methanol extract of peel of Citrus limetta fruits (MECL) was evaluated against EAC cell line in Swiss albino mice. Twenty-four hours after intraperitoneal inoculation of tumor EAC cells in mice, MECL was administered at 200 and 400 mg/kg body weight i.p. daily for nine consecutive days. On the 10th day, half of the mice were sacrificed for the estimation of tumor growth (tumor volume, viable and non-viable tumor cell counts), and hematologic parameters (red blood cells, white blood cells and hemoglobin). The rest were kept alive for assessment of survival parameters, i.e. median survival time and percentage increase in life span of EAC bearing mice. Intraperitoneal administration of MECL at the doses of 200 and 400 mg/kg for nine days to the carcinoma induced mice demonstrated a significant (P<0.001) decrease in tumor volume, viable tumor cell count, tumor weight and a significant (P<0.001) improvement in hematological parameters and life span as compared to the EAC control mice. The present study establishes marked and dose dependant anti-tumor effect of C. limetta fruit peel against Ehrlich ascites carcinoma bearing Swiss mice.