In this work the surface composition of immiscible blends of nylon-6/poly(cis-1,4-butadiene) cast from solution have been studied by X-ray photoelectron spectroscopy. First, a mixture of two solvents capable of dissolving both polymers was designed, and then the effects of the solution concentration, solvent ratio and bulk polymer ratio on the surface composition of the blends were investigated. The results are discussed in terms of a phase diagram and show that blend surface composition is determined by the combined influence of these parameters, the strongest defining which polymer enriches the surface.