Following the advent discovery of MAGE, cancer/testis (CT) antigens have been the centre of significant focus for a number of years based on their potential use for cancer therapy. CT antigens are a group of tumour-associated antigens that demonstrate expression in tumours with no expression in normal tissues with the exception of the cells of healthy testis and placenta. Due to their restricted level of expression, CT antigens are considered to be the most promising targets for tumour immunotherapy. Despite little knowledge regarding their function or cellular involvement, many members of this group have been found to be immunogenic and are being incorporated into clinical trials. The majority of CT antigens are encoded by genes that are located on the X chromosome (CT-X antigens) and have been exhaustively reviewed in the past. There has been less focus on CT antigens encoded by genes found outside the X chromosome: the so-called non-X-linked CT antigens. In this review, we concentrate on this latter collection of antigens, giving details regarding their level of expression, tissue distribution, immunogenicity, and their potential use for immunotherapy. We also highlight two particular non-X-linked CT antigens that this laboratory has studied for a number of years and describe the experiments used to characterise them.