Bone defects can be the result of physiological atrophy, diseases, or medical intervention. Bone regeneration under electrical stimulation has been proven to be a promising approach in cell experiments. However, there is a lack of evidence of the respective effect in animal trials. This is limited because there are no fully implantable stimulators at hand. Therefore, the aim of our present study is the description of requirements and design of an implantable electrical stimulator for bone regeneration experiments.