A judge at the High Court in London said on Friday that while Brown may have copied bits of the 1982 book The Holy Blood and the Holy Grail, that did not amount to a breach of copyright.
Judge Peter Smith, said: "Even if the central themes were copied, they are too general or of too low a level of abstraction to be capable of protection by copyright law."
Michael Baigent and Richard Leigh, authors of The Holy Blood and the Holy Grail, claimed that Brown's blockbuster "appropriated the architecture" of their non-fiction book.
Smith said it was not for him to decide whether Baigent was "extremely dishonest or a complete fool", but called him a "thoroughly unreliable witness".
In a case followed intensely by reporters, copyright lawyers and fans of The Da Vinci Code, Baigent and Leigh said Brown stole the central themes of their book and used them in his own, which has sold over 40 million copies worldwide.
Both books explore theories that Jesus married Mary Magdalene, the couple had a child and the bloodline survives.
Brown, who was not in court for the ruling, said the verdict "shows that this claim was utterly without merit".
Brown (L) won another ruling last
year against a New York author
In a statement, he said: "I'm still astonished that these two authors chose to file their suit at all.
"A novelist must be free to draw appropriately from historical works without fear that he'll be sued... This is a good day both for those who write and those who enjoy reading."
Random House, owned by German media conglomerate Bertelsmann AG, also welcomed the judgment, as did Sony Pictures, which is due to release a Hollywood film based on The Da Vinci Code in May.
Gail Rebuck, Random House's chairman and chief executive, said in a statement: "We are pleased that justice and common sense have prevailed."
Baigent and Leigh were denied leave to appeal and face a legal bill of over ?1 million ($1.75 million), although an increase in sales of their own book as a result of the publicity surrounding the case may ease the pain.
"This is a good day both for those who write and those who enjoy reading"
author of The Da Vinci Code
Holy Blood, like The Da Vinci Code, was published by Random House and some observers have suggested the court case was orchestrated by the publisher to boost sales of both books, a suggestion Random House rejects.
Rebuck said: "We never believed it should have come to court - and frequently tried to explain why to the claimants.
The case was the second of its kind involving Brown.
Last August, he won a ruling in New York against another writer who claimed he had copied elements of two of his books to write The Da Vinci Code.