Château Cantemerle is a winery in the Haut-Médoc appellation of the Bordeaux wine region of France, in the commune of Macau. The wine produced here was the final estate to be classified as one of eighteen Cinquièmes Crus (Fifth Growths) in the Bordeaux Wine Official Classification of 1855. Its absence from the classification map featured at the 1855 Exposition Universelle de Paris created some controversy, even though it has been listed on all maps published after 1856. Some sources will include an asterisk next to Château Cantemerle listing in reference to this controversy. The estate has a long history in the Haut-Médoc with records detailing its existence since at least the 12th century and wine production since at least the 14th century. In the 19th century, the estate was hard hit by the phylloxera epidemic as well as grapevine attacks of downy mildew, after which production dropped nearly 50%. Towards the end of the 20th century, the estate was sold to French insurance group Les Mutuelles d'Assurance du Bâtiment et des Travaux Public who have contributed significant investment in the estate's vineyards and winemaking facilities.
The status of Château Cantemerle as an original 1855 classification wine may be questioned as it was not included in the first publication of the classification, nor was it shown on the map that was displayed at the 1855 Exposition Universelle de Paris. It has been included on all listings dated 1856 and later. This was the result of an intense lobbying effort by Caroline de Villeneuve-Durfort who had supplied documentation to the brokers originally responsible for the price-based 1855 classification. Hence, its entry in the classification today is often accompanied by an asterisk denoting the only change in the classification that had occurred in more than 110 years.