The objective of this study was to evaluate whether prosthetic fitting before the age of one year is associated with better outcomes in children with unilateral congenital below-elbow deficiency compared to children fitted after the age of one. Twenty subjects aged 6-21 years were recruited (five prosthetic users and 15 non-users). The Child Amputee Prosthetics Project-Prosthesis Satisfactory Inventory (CAPP-PSI) and the Prosthetic Upper Extremity Functional Index (PUFI) were used to assess patient satisfaction and functional use of the prosthesis. Videotapes were used to assess motor performance. Initial prosthetic fitting before one year of age was related to use of a prosthesis for at least four years. Age at first fitting was not associated with satisfaction with the prosthesis, functional use of the prosthesis or motor skills. Discrepancies between ease of performance with prosthesis and usefulness of the prosthesis as well as between capacity and performance of activities were found. The video assessments showed impaired movement adaptation to some tasks in six subjects. In conclusion, early prosthetic fitting seems to have a limited impact on prosthesis use during later stages of life.