Reductive annealing was chosen as a method for the syntheses of Se modified Ru/C catalysts. Initial preparation of a 20 wt% Ru/C was performed by impregnating RuCl3 center dot 2H(2)O on Vulcan XC72 with subsequent conditioning using H-2 at 250 degrees C for 4 h. Surface treatment of Ru/C by SeO2 followed by reductive annealing produced Se modified Ru/C catalysts with a pre-determined Ru:Se = 1:0.15 and 1:1 a/o. Structural characterization was carried out using HRTEM while electrochemical characterization was performed using RDE measurements. It is concluded that the presence of Se on Ru has a positive effect on the oxygen reduction reaction of RuSe/C catalyst systems with an optimal loading of Se close to a Ru:Se ratio of 1:0.15 a/o. Overloading of selenium led to neutralization of its promoting effect.