Traditional robotic/mechatronic design has successfully exploited the attributes of heavy mechanical systems engineering, but future scientific trends suggest a need for technology that will emulate natural systems -biomimetic operation. This drive for new bio-mimetic principles is particularly prevalent in actuator design. This work will explore the design, using bio-mimetic principles, of actuators for the bipedal section of a humanoid robot. The paper will consider the design and selection of actuators and their incorporation into the legs of the humanoid. This will for the first stage of a humanoid standing 1.55m at the shoulder and weighing less than 25kg.