Moho depths or crustal thicknesses at four stations of the Ethiopian Seismic StationrnNetwork (ESSN) are estimated from Receiver Functions studies. We usedrnhigh quality seismic data recorded at ANKE (Ankober), DILA (Dila), HARE (Harar)rnand SEME (Semera) stations for earthquakes located at epicentral distances rangingrnfrom 30o to 100o and magnitude M 5:5. We applied frequency domainrndeconvolution technique to remove all effects from the earthquakes source andrnpropagation path to make the RFs dependent only on the structure beneath thernseismic stations. A linearized-iterative inversion is applied on the generated radialrncomponent of the Receiver functions. From the four stations in the study,rnthe minimum number of teleseismic earthquakes is 14 for Harar while the maximumrnis 39 for Ankober. The estimated values for the Moho depth are 42 1:7km,rn36 2km, 38 2kmand 26 2kmfor Ankober, Dila, Harar and Semera respectively.rnWe have achieved a reasonably good fit between the observed and synthetic RFsrnwhich demonstrates the goodness of the inversion. The lowest Moho depth is observedrnfor Semera station which implies a thinned crust while the highest crustalrnthickness is achieved for Ankober that lies along the western plateau margin. Thernsecond low Moho depth is calculated for Dila station while the one for Harar is anrnintermediate one. Our results agree with previous observations which strengthensrnthe fact that Moho depths estimated for stations that lie within the rift andrnrift margins are lower than those located in the plateaus. On the other hand, ourrnRFs inversions show low velocity gradient at about 15km depth at Semera stationsrnwhile high velocity gradient is noticed at Ankober station. This may implyrna cooled magma from previous dike or sill intrusions beneath Ankober stationrnwhile the observation at Semera indicates the existence of melt at that depth