A Multi Carrier Code Division Multiple Access (MC-CDMA) system's performance can get degraded due to intercarrier interference (ICI). The Doppler frequency or frequency drift between transmitter and receiver causes frequency offset which in its turn leads to ICI. The objective of the paper is to reduce the ICI in the MC-CDMA system using ICI mitigation techniques. Here, we have employed two techniques. The first method is self-cancellation technique, this technique has data conversion, real constant weighted data conversion, plural weighted data conversion and weighted conjugate transformation methods. The second technique is Extended Kalman Filter (EKF) method in which the frequency offset is estimated and then corrected using an estimated value. The EKF is introduced first time in MC-CDMA for the reduction of ICI. The EKF is employed for different frequency offset values. The simulation shows that the interference reduced to certain extend in EKF method when compared to self-cancellation technique (EKF provides the better performance than the selfcancellation technique). This analysis carried out for intervals of Bit Error Rate (BER).