Cancer-Testis (CT) antigens are by definition expressed in tumor but not in healthy tissue except testis and might represent ideal targets for antigen-specific immunotherapy. Here, we present the first comprehensive analysis of CT antigen expression in patients with head and neck squamous cell carcinoma (HNSCC). Tumor samples (N = 51), and adjacent healthy tissue from patients with HNSCC were analyzed for the expression of 23 genes designated CT antigens using RT-PCR. Patient sera (N = 39) were screened for IgG antibody responses against NY-ESO-1, MAGEA3, and SSX2. According to their expression pattern antigens were divided into four groups. ADAM2, LIP1, SLLP1, AKAP3, CTAGE, ZNF165, CAGE, and FTHL17 were expressed in tumor and healthy tissue at comparable frequencies. NY-TLU-57, GAGE1, SAGE1 were expressed more frequently in tumor samples than in healthy tissues. TPTE, LDHC, SPO11 were expressed neither in tumor samples nor in healthy tissue. 9 CT antigens were expressed only in the tumor tissue and may represent ideal candidates for active immunotherapy in HNSCC: MAGEA3 was expressed in 72%, SSX1 in 45%, MAGEC2 in 33%, MAGEC1 in 28%, BAGE in 17%, SSX2 in 16%, SCP1 in 12%, NY-ESO-1 in 6%, and HOM-TES-85 in 4% of cases. 86% of tumor samples expressed at least one, 69% expressed at least two, and 43% expressed at least three of these antigens. Three patients showed an antibody response against NY-ESO-1. In conclusion, we demonstrate here that HNSCC frequently express CT antigens. Furthermore, a relatively high percentage of tumors express more than one CT antigen opening the perspective for polyvalent antigen-specific immunotherapy.