The impact of manufactured nanomaterials on human health and the environment is a major concern for commercial use of nanotechnology based products. A judicious choice of selective usage, lower nanomaterial concentration and use in combination with conventional therapeutic materials may provide the best solution. Radio therapy is the most commonmodality for treating human cancer. The presence of radio resistant hypoxic cells in the large tumors prevent the achievement of complete response following radiotherapy. This demands the use of specific hypoxic radiosensitizers to modify the radiosensitivity of tumor cells. Various compounds are synthesized and tested to sensitize the tumor cells to radiiation. An ideal radio sensitizer should have low toxicity, high radiosensitizing efficiency for hypoxic cells and atleast effect on normal cells. The hypoxic cell radiosensitizer, sanazole [(N-2Â-(methoxy ethy)-2-(3Â-nitro-1Â-triazolyl) acetamide], commonly referred as (AK-2123), was complexed with siver nanoparticles, its cytotoxicity and radiosensitizing property inDaltons lymphoma Ascites cells were checked. The silver nanoparticle complex enhanced the radio sensitivity of the tumor cells and there was enhancement in radiation -induced apoptosis and cytotoxicity.