Le Marquis de Calon Ségur is the second wine (Deuxième Vin) of Château Calon Ségur, a prestigious Grand Cru Classé estate in the Saint-Estèphe appellation of the Médoc, Bordeaux, France. Distinct from the Grand Vin, Le Marquis is produced from separately identified vineyard plots and crafted to deliver immediate enjoyment with its own expressive identity. It is a blend primarily of Merlot and Cabernet Sauvignon, with small contributions of Cabernet Franc and Petit Verdot, aged approximately 17 months in oak barrels with roughly one-third new oak.

The wine presents an intense, deep dark red color approaching ink. On the nose it offers an exuberant bouquet of black fruits — cassis, plums, and blackberries — marked by notes of graphite, chocolate, cedar, and a hint of burning embers. The palate entry is tender and soft with generous, creamy tannins and beautiful finesse, while Saint-Estèphe's characteristic wet stone and slate minerality lingers through the juicy, structured finish. The wine is described as deliciously easy-drinking, silky, and expressive, reflecting the elegance of the Grand Vin while being approachable earlier.

It pairs beautifully with black pepper steak, roast pork, filet mignon, beef brisket, venison, roasted potatoes, and aged cheeses such as white cheddar or provolone. Alcohol content is approximately 13.5–15% ABV. The wine consistently earns scores of 90–94 points from major critics including James Suckling, Wine Advocate, Vinous Media, and Decanter. Best enjoyed now through 2035.