The Da Vinci Code debuted at number one on the New York Times bestseller list, and generated high praise from many critics for its entertainment value. Reviewing the novel for the New York Times, Janet Maslin declares, "In this gleefully erudite suspense novel, Mr. Brown takes the format he has been developing through three earlier novels and fine-tunes it to blockbuster proportion." On the other side of the Atlantic—and indeed, on the other side of the critical spectrum—Peter Millar writes in his review for the Times (London) that the novel "is without doubt, the silliest, most inaccurate, ill-informed, stereotype-driven, cloth-eared, cardboard-cutout-populated piece of pulp fiction that I have read." Whatever the reaction, reviewers most often took polarized views of the book initially. Whatever the reason, sales of the novel increased exponentially. As of 2005, the novel had been listed in the New York Times bestseller list for ninety-six weeks, even though it had not yet been released in paperback. Over twenty-five million copies had been purchased in the two years following its publication to generate more than $210 million in sales. Its world-wide success and controversial claims were deemed so dangerous that Lebanese religious leaders had it banned from the country, and Cardinal Tarcisio Bertone urged Catholics to boycott it.

The year after it was published, some critics began analyzing the reasons behind its success. Writing for the New Statesman, Jason Cowley notes that the novel brings out "many of the most urgent political themes of our time—religious extremism, the idea that history itself is a vast conspiracy, the power of secret networks and societies over our lives, the global reach of the internet, the omnipresence of satellite surveillance and other new technologies." More specifically, Cowley argues that "In the aftermath of the events of September 2001 and the invasion of Iraq, in a world where a mysterious and opaque global network of religious terrorists called al-Queda threatens the west as well as, it is believed, communicating via encoded messages," the novel "carries a powerful political charge."

Capitalizing on the novel's widespread success, networks produced a number of programs exploring its subjects. ABC sent reporter Elizabeth Vargas on an international journey to interview scholars about the novel's claims. The special, titled "Jesus, Mary and Da Vinci," aired in the fall of 2003. "Da Vinci Code: The Full Story," another program to explore the novel's issues, aired on the National Geographic Channel, attracted more viewers than the channel had for any other program in its history. As a summary of Christian scholars' critiques of the novel, PAX aired "Breaking The Da Vinci Code" in early May of 2005, taking its title from Darrel Bock's critical book. The History Channel produced a two-hour special titled "Beyond The Da Vinci Code," which aired in late May of 2005.

Many religious scholars published critical books of their own, taking issue with Brown's sensational assertions, voiced in interviews, that he believes in his novel's theories; they also took exception to the novel's astounding market success. Among those to debunk the novel are Carl E. Olson and Sandra Miesel in The Da Vinci Hoax: Exposing the Errors in "The Da Vinci Code" (2004). The Archbishop of Chicago, Cardinal Francis George, speaking in Ignatuis Books, calls The Da Vinci Hoax: Exposing the Errors in "The Da Vinci Code" "the definitive debunking" of The Da Vinci Code. In a pamphlet for Our Sunday Visitor, Amy Welbourn excerpts from her book, De-Coding Da Vinci: The Facts Behind the Fiction of "The Da Vinci Code" (2004). In it, she calls The Da Vinci Code "logically and historically flawed," and cites that Brown holds "no advanced degrees in religion." Other scholars and critics take more objective historical perspectives, with an aim of providing historical information that is sometimes at odds with the facts in Brown's novel. These books include Simon Cox's Cracking the "Da Vinci Code": The Unauthorized Guide to the Facts behind Dan Brown's Bestselling Novel, and Sharan Newman's The Real History Behind the "Da Vinci Code" (2005).

Additional critical overview from Greg Beatty, eNotes contributor:

The Da Vinci Code dominated U.S. bestseller lists from the time of its release in late February 2003 until well into 2004; it remained a bestseller in 2005, with worldwide sales of roughly twenty-five million. Critics fairly universally praised The Da Vinci Code upon its publication, although many failed to see that Brown’s novel would spark such controversy and discussion. Publishers Weekly began the praise by calling it “an exhaustively researched page-turner about secret religious societies, ancient coverups and savage vengeance.” In saying that “Brown has assembled a whopper of a plot that will please both conspiracy buffs and thriller addicts,” the magazine summarized the charm that would magnetize millions of readers. However, it cautioned that “Brown sometimes ladles out too much religious history at the expense of pacing, and Langdon is a hero in desperate need of more chutzpah.”

In contrast, The San Francisco Chronicle maintained that Brown “does a terrific job of spooling out the controversial history lesson without ever lapsing into pedantry or preachiness.” The Washington Post went out of its way to praise the book’s academic qualities by saying that “the novel alternates between conventional chase scenes and the scholarly digressions that provide its special charm.”

The New York Times, as well, declared that The Da Vinci Code was a “gleefully erudite suspense novel” and claimed that Langdon was “enormously likable.” Although realizing that Brown was “drawn to the place where empirical evidence and religious faith collide,” the Times was content to praise The Da Vinci Code for being “breezy enough even to make fun of its characters’ own cleverness.”

Salon.com was similarly to see the book as a dazzling product from “a writer who hits on a snazzy gimmick and then mines it for all it’s worth.” Salon disclaimed any deeper message to Brown’s book by declaring that “for all the facts he throws around,” Brown “operates squarely in the territory of the pop bestseller.” The Post, while observing that “in a great many ways, the novel has a feminist slant,” in summary commented only that “Brown keeps the pace fast, the puzzles that lead to the Grail are exceedingly clever, and there is a flurry of surprises and betrayals before the mystery is finally solved.”

A reviewer for The Boston Globe seemed to show the most foresight of any critic by declaring that Langdon embarks “on a fascinating journey through a covert, enigmatic world revealed through a seemingly endless collection of codes, puzzles, anagrams, cryptograms, and messages hidden not only in da Vinci’s art but in things we think we know well.” In concluding that “[w]e are deceived, it seems, not only by those who seek to deceive us, but also by our failure to understand the complex nature of ideas and common beliefs,” the Globe prophesized that Brown’s novel would provoke literally millions of people to examine their own traditional beliefs and question the teachings they had received from their culture and their religious authorities.