A 59-year-old man admitted for IM had a 3-way cannula inserted into the right subclavian vein for 31 days. Autopsy revealed a circular firm thickening of the venous wall. Histology identified it as chondroid and osteoid tissue replacing adventitial connective tissue. Unusual chondroosteoplas- tic metaplasia not described up to now is discussed as about its causes.

        Key words: subclavian vein - chondroosteoplastic metaplasia of vessel wall - cannulation - iatroge- nic injury - hypoxia