TRAIL is a member of TNF superfamily and binding of TRAIL to its receptors induces cell death with apparent specificity for carcinoma cells compared with normal epithelium. On this basis, a number of TRAIL-targeted therapies are currently under investigation as anti-cancer agents. Recent studies in our lab have shown that membrane bound forms of both FasL and CD40L are more potent in cell death induction, suggesting that a membrane bound TRAIL could be more effective in cell death induction compared to the wild-type or the soluble counterparts. TRAIL gene therapies have demonstrated that ex vivo infection of cancer cells with a recombinant adenovirus expressing TRAIL (RAdTRAIL) enhances apoptosis and promotes tumour regression. In the present study, we have generated two adenoviral vectors. The first one expressing wild-type TRAIL (RAd wtTRAIL) that subject to cleavage from cell membrane and the second adenoviral vector expressing fusion CD40LTRAIL protein that is resistant to metalloproteinase cleavage (RAd CD40LTRAIL). The direct effects of these viruses were examined on TRAIL receptor positive carcinomas either alone or in combination with different chemotherapeutic drug. The RAd CD40LTRAIL that expressed the membrane bound CD40LTRAIL was found to exhibit more cell death than the RAd wtTRAIL. This cell death was through the activation of caspase 3/7.