This paper deals with a research work aimed to develop a new three degrees of freedom (DOF) mechanism for humanoid robots. The main idea is to build hybrid (3DOF) mechanism, which avoids the drawbacks of the serial and parallel mechanisms. The new solution has to merge the advantages of both classical (serial and parallel) structures in order to achieve optimal performances. The proposed mechanism can be used as a solution for several modules in humanoid robot. The hip mechanism is taken as an example to illustrate the contribution of this paper. To evaluate the performances of the system, simulation of this new mechanism is carried out with Adams software. Geometrical and Kinematic models are developed and included in the simulation tool. Based on biomechanical data, analysis of the new kinematic structure is carried out. The design of the proposed solution is then described. Finally the first prototype developed for the HYDROïD robot's hip is presented. This mechanism is a part of an International patent accepted at INPI- France.