Electronic and magnetic calculations were based on density functional theory within the generalized gradient approximation for II-VI compound semiconductor TiO2 doped with single impurity Os and Mo; these compounds are half-metallic ferromagnets in their ground state with a total magnetic moment of 2 mu(B) for both systems. Then, doping TiO2 with double impurities (Os, Mo) was performed. As a result, Ti1-2xOsxMoxO2 with x = 0.065 is a half-metallic antiferromagnet with 100% spin polarization of the conduction electrons crossing the Fermi level, without showing a net magnetization. Moreover, the Ti14OsMoO32 compound is stable energetically than Ti1-xMoxO2 and Ti1-xOsxO2. The antiferromagnetic interaction in the Ti1-2xOsxMoxO2 system is attributed to the double exchange mechanism, and the latter could also be the origin of their half-metallic behavior. (C) 2014 Elsevier B.V. All rights reserved.