We perform first-principles spin polarized calculations of the electronic structure of GaN doped with 6.25% of Ti. We show that the Ti dopants are found spin polarized and order ferromagnetically in GaN, forming a dilute magnetic semiconductor. The Ti-doped GaN favors ferromagnetic state which can be explained by double-exchange mechanism, and a Curie temperature above room temperature can be expected. Since there is no magnetic element in this compound, Ti-doped GaN is likely to be a promising dilute magnetic semiconductor where ferromagnetic precipitate problems can be avoided. (c) 2007 Elsevier B.V. All rights reserved.