Testing rotor blades of wind turbines is essential to mitigate financial risks caused by serial damages. Present day uniaxialdynamic tests are time consuming and often inaccurate regarding the applied loading. This thesis proposes a fasterfatigue test method by loading the two primary directions at the same time. In addition, a more realistic test, comparedto uniaxial tests, is accomplished by loading larger areas of the blade cross-sections. To achieve this, an elliptical biaxialdynamic excitation is used. To fulfill the industry requirement for cost effective tests, a relatively simple test setup wasdeveloped, still achieving an elliptical dynamic excitation of the rotor blade. Two methods for an accurate determinationof the applied loadings for dynamic fatigue tests are described. These calibration tests use easily measured values andsimple analysis to achieve accurate test load measurements in a cost-effective way.