Cancer is one of the health concerns in modern societies. The application of nanotechnology in medical sciences has created new possibilities for the diagnosis, imaging and the treatment of tumors in humans. The present article reviews the application of marine-based gold nanoparticles in diagnosing and treating cancer. The main data were collected from research article on the application of different marine-based gold nanoparticles in detecting and imaging cancer cells as well as in drug delivery system in treatment of cancer. Chitosan is the most used marine natural compound used to fabricate gold nanocomposites and the most reported application of this type of nano-composites is related to drug delivery system. Despite the excellent anticancer potential of different marine natural products, less studies have been conducted on the use of their compositions with gold nanoparticles in cancer therapy than other materials. Moreover, most reports available in this filed are related to their application as a drug delivery system not anticancer drug. In general, there are still challenges and limitations to the use of nanoparticles in medicine, it is hoped that in the near future nanoparticles will create a dramatic revolution not only in oncology but also in medicine.