Deflighting is used to prevent large captive birds from escaping by limiting their ability to fly. This practice deprives birds of this normal behaviour, but can allow them to express other behaviours that would be suppressed if they were confined to cages or aviaries. The potential negative welfare issues associated with deflighting include the stress of capture and restraint, pain and discomfort associated with the procedure and during recovery, risk of post-operative infections, risk of neuroma formation which could lead to pain, and loss of the ability to fly. The potential practical and welfare advantages of deflighting include a reduction in the need to closely confine or cage birds to prevent them from escaping, and deflighting may be the only way of keeping particular birds in an open situation for display, such as in parks or zoos. In these respects, there must be a balance between the requirement for this practice and the welfare compromises it introduces for birds. By outlining temporary and permanent methods and the complications involved, the following review highlights potential welfare problems and discusses ways of avoiding them. It also evaluates the necessity of deflighting and the need for careful risk assessment.