Combination vaccines of the NY-ESO-1 protein complexed with cholesteryl pullulan (CHP), CHP-NY-ESO-1, and the truncated 146HER2 protein with CHP, CHP-HER2, were subcutaneously administered with the immuno-adjuvant OK-432 to eight esophageal cancer patients. Vaccination was well-tolerated. NY-ESO-1- and HER2-specific antibody responses were analyzed using the patients' sera and samples from previous single CHP-NY-ESO-1 or CHP-HER2 vaccine trial. The responses to NY-ESO-1 in the combination vaccine study were comparable to the single vaccine. For responses to HER2, there were fewer antibody responses in the combination vaccines. Although there were marked individual variations in the antibody responses to the NY-ESO-1 and HER2 antigens, the reaction patterns to these antigens were comparable within each patient. Antibodies to OK-432 were not augmented. Protein cancer vaccines targeting multiple antigens are feasible.