AALBORG, August 17, 2014 (AFP) - Warren hit five birdies in a final round of 68 for a total of 275 and nine under.
He was pushed all the way by Dredge, who went round in 70 for seven under overall while England's Phillip Archer was third, five shots off Warren.
"I felt the last couple of years I've been close to winning a couple of times but for whatever reason it hasn't quite happened for me, whether I've made mistakes or someone else has played really well," said Warren.
"This summer I feel more confident than I've ever done. Today I kept telling myself I was swinging the club really well and I was confident in what I was doing."
Dredge, the halfway leader, was left looking for his first title in six years.
"In a way there are mixed feelings in that if someone said they'd give me second at the beginning of the week it is a great result, considering I've not had a chance to win in a long time. But it was a chance to win a tournament," he said.
"Marc did play really well and I didn't play well enough, but it would have been nice to have pushed him a little harder coming down the last few."
Leading Danish Open fourth and round scores on Sunday (GBR/IRL unless stated; par 71):
275 - Marc Warren 71 70 66 68
277 - Bradley Dredge 66 68 73 70
280 - Phillip Archer 70 70 71 69
281 - Thomas Bjorn (DEN) 66 73 73 69, Eddie Pepperell 73 68 71 69, Oliver Fisher 75 65 72 69
282 - Lasse Jensen (DEN) 72 69 74 67, Thorbjorn Olesen (DEN) 69 70 72 71
283 - Mikael Lundberg (SWE) 72 69 71 71, Gareth Maybin 75 67 68 73, Stuart Manley 73 69 69 72, Shiv Shankar Prasad Chowrasia (IND) 70 71 71 71, Rikard Karlberg (SWE) 73 70 71 69, Simon Wakefield 71 67 72 73
284 - Richard Bland 71 74 68 71, Soren Kjeldsen (DEN) 71 73 70 70, Craig Lee 73 72 69 70, Roope Kakko (FIN) 70 71 73 70, David Drysdale 71 68 76 69, David Lipsky (USA) 72 71 73 68, Tom Lewis 72 70 72 70
285 - Shiv Kapur (IND) 73 68 74 70, Andrew McArthur 72 72 72 69, Paul Waring 75 66 72 72, Daniel Im (USA) 72 68 76 69, Simon Dyson 77 69 70 69, Andreas Harto (DEN) 70 72 75 68
Selected:
287 - Wade Ormsby (AUS) 71 72 76 68
289 - Kim Sihwan (KOR) 70 75 73 71
290 - Brandon Stone (RSA) 73 73 74 70
294 - Gaganjeet Bhullar (IND) 73 70 75 76