The development of ergonomic tools responds to health protection needs on the part of workers, especially the work related musculoskeletal disorders of the upper limbs and to the development of ergonomic tools to take into account the needs of the factories. Only an ergonomic design process can enable tool manufacturers to meet these requirements. Three factors are involved: integration of ergonomics into the design process, definition of the different ergonomic stages involved, and finally knowledge of the different factors involved in hand tool design. This document examines these 3 elements in more detail and presents briefly a project of research whose main purpose is to integrate ergonomic criteria into a design process.