This paper presents the application of fuzzy logic based supplementary controller, for Interline Power Flow Controller (IPFC), to enhance the damping of low frequency oscillations in the Single Machine-Infinite Bus (SMIB) power system installed with IPFC. The fuzzy logic based IPFC controller using Mamdani type inference system is designed with generator speed and rotor angle as its input signals. The proposed method is applied to control the input signal of IPFC and thus improving the power system stability. The effectiveness of the controller in damping the power system oscillations is demonstrated with varying operating conditions.