Transdermal drug delivery systems are adhesive, dug containing devices of defined surface area that deliver a pre-determined amount of drug to the surface of intact skin at a pre-programmed rate. These systems provide drug systemically at a predictable rate and maintain the rate for extended periods of time. In this work an attempt was made to formulate and evaluate TDDS for sustained release Atorvastatin calcium by solvent casting method. Low molecular weight, good permeability of Atorvastatin calcium made it a suitable drug candidate for the development of transdermal patches. The main objective of formulating the transdermal system was to prolong the drug release time, reduce the frequency of administration and to improve patient compliance. We sincerely hope that this book will helpful to student as well as industry and academic professionals involved in pharmaceutical and other related science.