The purpose of this research was to develop a matrix-type transdermal therapeutic system containing Diclofenac acid (DA), Pressure Sensitive Adhesive (PSA) by the solvent evaporation technique. Different concentrations of Labrasol, oleic acid and triacetin were used to enhance the transdermal permeation of DA. Polyethylene monolayer film as a backing membrane and Silicone coated polyester film as a release liner preferred in preparation of transdermal patches. Formulated transdermal patches were physically evaluated with regard to percentage moisture absorption, thickness, weight variation, drug content, tensile strength, % elongation, folding endurance. In vitro skin permeation studies of formulations were performed by using Franz diffusion cells. Formulation containing 5% drug, 85% adhesive and 10% triacetin as permeation enhancer showed best in vitro skin permeation through human cadaver skin as compared to all other formulations. The results were found to follow zero order kinetics. These results indicate that optimized formulation has shown optimum release in concentration independent manner.