Minor components in a porous electrode of solid oxide fuel cells (SOFCs) can affect the electrode performance. In this study, we focus on minor components derived from raw materials and production processes. Standard polycrystalline dense cathode samples of La0.6Sr0.4Co 0.2Fe0.8O3-δ (LSCF) were prepared using high purity raw materials by Pechini method. To evaluate the effects of the minor components on LSCF performance, minor components such as Ba, Ca, Al and Si were added to the LSCF samples. Chemical diffusion coefficient (Dchem) and surface exchange coefficient (ktr) were obtained as cathode performance factors by the conductivity relaxation measurement. The results showed that Al and Si have mostly negative effects for oxygen reduction reaction on LSCF while Ba and Ca were inert or showed positive effects for the cathode performance. We also discussed the mechanism of positive effect of Ca (Dchem,STD 〈 Dchem,Ca and ktr,STD 〈 ktr,Ca ) using XPS measurement. ©The Electrochemical Society.