Abstract: Medium baseline reactor experiments (Double Chooz, Daya Bay and RENO) provide a unique opportunity to test the presence of very light sterile neutrinos. We analyze the data of these experiments in the search of sterile neutrinos and also test the robustness of ? 13 determination in the presence of sterile neutrinos. We show that existence of a light sterile neutrino state improves the fit to these data moderately. We also show that the measured value of ?_ 13 by these experiments is reliable even in the presence of the sterile neutrinos, and the reliability owes significantly to the Daya Bay and RENO data. From the combined analysis of the data of these experiments we constrain mixing of a sterile neutrino with ?m^2_{41}~(10^{-3}-10^{-1}) eV^ 2 to sin^2 2?_{14}<0.1 at 95% C.L.