In 1993 a multicenter study was undertaken to evaluate the safety of allowing an athlete to participate in his sport with the protection of a sports cast while an injury was healing. This study was conducted prospectively by 6 centers that involved 14 physicians in two states. Thirty-four athletes were identified to be involved in this study. Information obtained includes type of injury, method of protection, length of protection, healing rates, and whether the individual was worsened or if a team member opponent was injured from a cast or splint. Additionally, a continuing study will be presented of 300 patients from our facility from 1994 to 2001 with regards to the same information as the 1993 study. In our studies and our review of the NFL, NCAA, and high school injuries, no cases of a fracture or injury was identified as being made worse or that healing time was interrupted. Current rules for the use of a sports cast in the NFL, NCAA, and National Federation of High School Associations are reviewed. The fabrication and use of the sports cast including protocols are discussed. The conclusion is that sports casting appropriately applied, and when indications are followed, is a safe practice to return an athlete to his sport in-season.