Cancer is still one of the most common causes of death today despite advances in its detection and treatment. The present article reviews the application of marine-based gold nanoparticles in the diagnosis and treatment of cancer. The main data were collected from original research articles on the application of different marine-based gold nanoparticles in detecting and imaging cancer cells as well as in drug delivery systems and treatment of cancer. The results show the excellent anticancer potential of both gold nanoparticles and natural marine products. The most studied marine-based gold nanomaterial was chitosan-based ones, in which the role of chitosan is a stabilizer not an anticancer agent. Despite the excellent anticancer potential of different marine natural products, limited studies have been conducted using gold nanoparticles in their composition in cancer therapy. Moreover, most of these studies are related to their application as a drug delivery system not an anticancer drug. Although there are serious challenges in the application of nanoparticles in medicine, marine-based gold nanomaterials may promise an interesting novel strategy in the oncology field.