Patagial wing tags are commonly used for identification of Red Kites (Milvus milvus) for postrelease monitoring, as they are easy to apply, affordable, permanent, and are apparently safe. The Red Kite was successfully reintroduced in the UK in the second half of the 20th century and postrelease health surveillance has been achieved through radio and satellite tracking, monitoring nest sites, and pathologic investigation of Red Kites found dead. This study reports on pathologic findings associated with the use of patagial wing tags in three of 142 (2.1%) wing-tagged Red Kites examined postmortem since the beginning of the reintroduction project in 1989. In these three Red Kites the presence of the patagial wing tags was associated with inflammatory lesions. Further surveys of the potential short- and longer-term negative effects of patagial wing tags on Red Kites and other birds are advocated; the future use of patagial wing tags in raptors should be carefully monitored.