  Medium baseline reactor experiments (Double Chooz, Daya Bay and RENO) provide
a unique opportunity to test the presence of light sterile neutrinos. We
analyze the data of these experiments in the search of sterile neutrinos and
also test the robustness of theta_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
theta_{13} by these experiments is reliable even in the presence of 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
the mixing of a sterile neutrino with mass squared difference in the range of
(10^{-3}-10^{-1}) eV^2 to sin^2 2 theta_{14} <0.1 at 95 % C.L..
