The development of user interfaces is influenced byvarious challenges in recent years. These areforemost caused by an increasing complexity of theunderlying applications, the use of applications ondifferent devices and by different types of users andby frequently changing application environments.Model-based user interface development approacheshave been shown to be suitable to face thesechallenges. However, creating, transforming andlinking the various included models are complextasks. Employing patterns can reduce complexity byproviding an advanced concept of reuse. In this booka general approach of applying patterns inmodel-based design of user-interfaces is suggested.The components of the approach and the underlyingsteps are explained in detail. An example case isused to illustrate the suggested methodology. Finallya set of concrete patterns that can be employed inthis context is introduced.