Mesothelioma of peritoneum is a rare malignancy of serosal membranes. Here we report a case of 55year old female with mass per abdomen reported as epithelioid type of peritoneal mesothelioma. The diagnostic challenge in our cases was due to non specific presentation and the varied histologic morphology of tumor cells for which immunohistochemical studies with markers calretinin, vimentin, cytokeratin 20, cytokeratin5/6, CD34 and HMB34 had to be performed to arrive at the diagnosis. The tumor cells showed positvity for calretinin, vimentin and cytokeratin 20. The final diagnosis was possible due to correlation of histological and immunohistochemical characteristics been consistent with mesothelial origin.