We report four new times of minimum light and the improved ephemeris for the well known contact binary AM Leo. The O-C diagram, constructed with all reliable timings found in the literature was analyzed and the the light-time effect in the system was confirmed. We found a periodicity of 44.82 years in the O-C residuals with an amplitude of 0.0058 day. The periodic curve representing the O-C values is asymmetric indicating a large eccentricity of 0.73 of the third body orbit. The mass of the third body is found to be 0.175 M-circle dot for the orbital inclination of the eclipsing pair's orbit.