Oxygen nonstoichiometry (delta) and transport properties of Y0.08Sr0.92Fe0.1Ti0.9O3-delta (YSFT01) were assessed for the understanding of charge compensation mechanism, and electronic and transport behavior of co-doped SrTiO3 systems having transition metal acceptor-cation, which are being considered as potential anode materials in solid oxide fuel cell (SOFC). Oxygen nonstoichiometry of YSFT01 was measured by thermogravimetric analysis (TGA) as a function of oxygen partial pressure (P-O2) and temperature. The delta isotherms indicated that the valence of the variable-valence acceptor cation Fe changed from Fe3+ to Fe2+ with decreasing P-O2. Total conductivity of YSFT01 showed a delta-dependent trend and in p-type region when Fe existed as Fe3+, total conductivity decreased with decreasing P-O2, but in n-type region when Fe3+ started reducing to Fe2+, total conductivity increased with decreasing P-O2. The chemical diffusivity ((D) over tilde) and surface exchange coefficient (k) of oxygen were calculated from the DC conductivity relaxation measurement and at 1000 degrees C they were 8.1 x 10(-6) cm(-2) s(-1) and 3.3 x 10(-4) cm s(-1), respectively. Oxygen-ion conductivity was calculated as a function of P-O2 from the chemical diffusivity and nonstoichiometry results, and it increased with increasing temperature; it was nearly constant in higher P-O2 regime but in low P-O2 regime it increased with decreasing P-O2. (C) 2013 The Electrochemical Society. All rights reserved.