The 2003 Cos d'Estournel, a Bordeaux Blend from the St Estephe sub-region of Bordeaux, France, has garnered impressive reviews from professional critics, solidifying its reputation as a robust and complex red wine. Produced by Cos d'Estournel, this wine is notable for its deep garnet-brick color and a blend of 68% Cabernet Sauvignon, 30% Merlot, and 2% Cabernet Franc.

Wine Spectator's James Molesworth awarded it 93 points, praising its "juicy edge" with flavors of dark currant, fig, and a hint of bramble. Molesworth also noted the wine's "ample tobacco, ganache, and humus notes," which contribute to its character, leading to a "long, smoldering finish." The only minor drawback mentioned was a "slightly grainy structure."

Wine Enthusiast's 95-point review from May 2006 highlights the wine's power and polish, with aromas of "new wood, spice, and black fruits." The review underscores its density and ripeness, resulting from a high percentage of Merlot, and describes the wine as "massive," combining the heat of the 2003 vintage with significant tannins typical of Saint-Estèphe.

Robert Parker's Wine Advocate, also giving it 93 points, described the 2003 Cos d'Estournel as having an "herbal nose" with elements of dried Mediterranean herbs and roasted meats, complemented by crème de cassis, stewed plums, and unsmoked cigars. The review emphasizes its full, rich, and concentrated palate, with earthy and savory accents and an herbal lift to the finish.

Neal Martin's Wine Journal gave the wine an exceptional 96 points, noting its "flamboyant, sumptuous bouquet" with scents of redcurrant, raspberry, vanilla, and graphite. Martin observed that the wine has become more focused over the years, showing fine definition and minerality towards the long finish.

James Suckling offered a stellar review, rating it 98 points and describing it as "dense and powerful" with "very ripe fruit yet an underlying freshness and complexity." He highlighted flavors of tobacco, dried fruit, and fresh spices such as lemon grass and Thai basil, calling it "layered and long."

Decanter, while slightly more reserved at 92 points, praised the wine's quality and surprising freshness, noting its array of "soft leather, truffle, spice, and fig." The review highlighted the wine's aging potential, aided by the clay subsoils of St-Estèphe and old Merlot vines.

Overall, the 2003 Cos d'Estournel is a well-regarded wine with a complex profile, praised for its power, richness, and aging potential.