Atorvastatin is a statin molecule, which is used for the treatment of hypercholesteremia to prevent cardiovascular disease. It is available as oral dosage form with four strengths; 10mg, 20mg, 40mg, and 80mg, it has low bioavailability due to its first pass metabolism in the liver and gastrointestinal tract. Atorvastatin has serious adverse side effects especially in liver and leads to myalgia and myopathy. In this study, a new microemulsion was developed using Dimethyl Sulfoxide, Polyethylene glycol400, Isopropyl myristate, and non-ionic surfactant Tween 80 for transdermal of Atorvastatin to improve bioavailability and reduce side effect. The MEs formulae were characterized in vitro using Franz cell, droplet size and rheological properties. The formula which contains 800mg Atorvastatin calcium, 4ml Dimethyl Sulfoxide, 2ml Polyethylene glycol400 and,4ml Isopropyl myristate gave us a clear stable microemulsion with high flux rate 10.078mcg/cm2/hr. it was tested orally and transdermally in vivo using rats. In transdermal application it gives maximum concentration 1.02mcg/hr, 5hr Tmax, and long duration time around 48hr without any irritation on the skin and no adverse effects had appeared on rats. No significant elevation in Creatinine Kinase and Alanine Transferase has been recorded in transdermal application comparing to oral application.