The present research investigates the sol–gel route using Pechini, citrate and alkoxide methods in order to obtain strontium doped lanthanum manganite perovskite La0.5Sr0.5MnO3 (LSMO) as nanometric materials. The electrocatalytic activity of carbon supported perovskite denoted (LSMO/C) used as an electrocatalyst for oxygen reduction reaction (ORR) in 0.1 M KOH electrolyte has been studied using a rotating disk electrode. The oxide powders were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Brunauer–Emmett–Teller (BET) method and transmission electron microscopy (TEM). X-ray diffraction results showed that the powders were primarily identified to a perovskite structure phase La0.5Sr0.5MnO3 with nanometric sized particles of about 20 nm and homogeneous morphology. Results related to the electrochemical study of ORR showed that the perovskite oxide synthesized by the Pechini method yielded an electrode material with improved electrochemical activity compared to those elaborated through citrate and alkoxide methods.