We present here a method for the calculation of effective-cluster interactions for semi-infinite solid alloys required for the study of surface segregation and surface ordering on disordered surfaces. Our method is based on the augmented-space recursion coupled with the orbital-peeling method of Burke in the framework of the TB-LMTO. Our study of surface segregation in CuNi alloys demonstrates strong copper segregation and a monotonic concentration profile throughout the concentration range.