We study the joint effects of viscosity, resistivity and ion-neutral collisions on Alfvén surface waves propagating along a partially ionized plasma - vacuum interface. Applying boundary conditions at plasma-vacuum interface, we obtain the dispersion relation for Alfvén surface waves and solve it numerically. For different values of resistivity and neutral gas friction parameters, the variation of real and imaginary parts of wave number with viscosity parameter are shown graphically. It is found that two-mode structure of Alfvén surface waves results due to the combined effects of resistivity, viscosity and ion-neutral collisions. These results might be useful for studying the behavior of Alfvén surface waves in laboratory and space plasmas.