X-band electron spin resonance (EPR) spectra were recorded in the temperature range 150–320 K on powdered samples of polycrystalline LaMn1-xCoxO3 (0.1⩽x⩽0.5) synthesized by citrate precursor method. The temperature dependence of the EPR spectra parameters like, the peak-to-peak linewidth (ΔHpp) and the EPR intensity, was analyzed. Both the EPR line intensity and the linewidth decreased by increasing the temperature. On the other hand changes in the lines shape from paramagnetic to ferromagnetic state were observed as a function Co content. This behavior correlates well with that observed in the transition temperature determined by a.c. susceptibility measurements.