This paper presents two approaches of observer based stabilization for Takagi-Sugeno (T-S) systems with immeasurable premise variables in continuous time case. These approaches are based on the description of the state estimation error by a T-S model. To design the observer based stabilization law, the concept of PDC (Parallel Distributed Compensation) is employed, the sufficient stabilization conditions are proved and expressed in the form of Linear Matrix Inequalities (LMI). The performances of these approaches are tested by simulation for an illustrate example and a physical system representing a two-link robot.