Methods for the fusion bonding repair of thermoplastic resin composites are discussed. Depending on the damage modes, thermoplastic resin composites may be repaired by welding on a patch or by thermal reforming. The merits and shortcomings of patching by fusion bonding are discussed and compared to those of adhesive patching. Resistance heating and induction heating with susceptors are considered to be suitable for patching type repair. The processing parameters and critical problems for the field repair application of these methods are investigated. Healing type repair, or thermal reforming, is based on the concept of crack healing of polymers. This technique is particularly interesting for repair of delamination. However, healing type repair requires relatively high pressure which can be achieved generally only at well equipped repair depots.