XPS and UPS investigations of ultrathin films of In/Ag and Ag/In, deposited onto the W( 1 1 0) surface in the ultrahigh vacuum conditions have been performed. Indium and silver films were formed by " in-situ'' evaporation on W( 1 1 0) substrate. XPS and UPS studies have been performed by means of SCIENTA ESCA200 instrument. The changes of In4d core-level and Ag4d valence band emissions with increasing Ag and In coverage were monitored to observe the energy shift and shape of the spin - orbit doublet of In4d and Ag4d lines in the Ag/In/W and In/Ag/W systems. UPS ( HeI and HeII) measurements were supported by XPS AlK alpha measurements of In3d and W4p levels, as well as by investigations of Ag3d levels. XPS and UPS data allowed to evaluate the coverage and make conclusions concerning intermixing and surface alloying in the In/Ag/W and Ag/In/W systems. W( 1 1 0) substrate can be cleaned after each deposition by thermal desorption and no alloying in the In/W and Ag/Wsystems is observed. (c) 2008 Elsevier B. V. All rights reserved.