Orthogonalfrequencydivisionmultiplexing(OFDM)isafrequency-divisionmultiplexing (FDM) scheme used as a digital multi-carrier modulation method. Many sub-carriers that are parallel, narrow band and orthogonal to each others are used to carry the data over a given channels. But, Carrier frequency offset (CFO) can harmfully influence the performance of OFDM systems, since they can result in inter carrier interference. ByusingapilottonebasedtechniquethispaperestimatedCFOinOFDMrelaynetworks. Thesimulationresultindicatedthatasthenumberofpilottoneincreasestheaccuracyof the estimated channel increases. The best result is obtained at 30dB with 32 pilot tones, which is around 0.04 for MMSE and 0.07 for LSE. However, the increment of pilot tones reduces little bit the bandwidth efficiency and also need additional energy. On the other hand, pilot tone based estimation techniques out performs Moose and Cyclic Prefix (CP) based techniques in CFO estimation.