The objective of this thesis study is to propose novel cable-constrained parallel mechanisms for walking machines. According to the literature, hybrid structured parallel mechanisms can overcome mechanical design, control system and workspace limitations compared to other structures. This thesis study introduces two novel hybrid structured leg mechanisms comprising rigid links and passive cables. Kinematic structure of the proposed mechanisms are (UPU-2Pa)-(UPU-2Pa)and (UU-2Pa)-P. Both designs have a hip, a knee and a foot platform. Two rotational constraints about horizontal axes are added to the moving platforms by using parallelograms with passive cables. The rotational constraint about the vertical axis is provided by rigid links and joints. Thus, the proposed designs have pure translational motion. The detailed analysis of the mechanism design with anchored cables is conducted. A CAD model is constructed and a dynamic simulation for human-like gait trajectory is performed in SolidWorks® environment. Once the computed actuator torques and forces are found suitable, a first prototype is built to check the proposed solution. Considering the problems encountered in this first prototype, a second prototype of the (UU-2Pa)-P mechanism is built. The prototype is operated using a real-time PCI controller and experimental results are presented. The mechanisms presented in this thesis is one of the few cable-constrained parallel manipulator designs in the literature. Such a manipulator design is used for a walking machine for the first time. The prototype and test results are quite satisfactory, so hopefully more detailed research can be conducted on this topic in the future.