Hepatitis B is the most common serious liver infection in the world. Worldwide, about 350 million people are chronic carriers of the hepatitis B virus (HBV). These carriers often need enduring antiviral treatment. My research aims the improvement of treatment possibilities. Therefore, we focus on bioinformatic systems that help us to understand the underlying principles of therapy success and therapy failure. We will build a Web Service that predicts drug resistance w.r.t the available HBV drugs. This system will be based on a statistical model and a set of virological measurements. I will talk about the lesson learned from HIV and the first steps in the development of a model for HBV resistance.