Discovery, isolation, biochemical/pharmacological characterization, pre-clinical and clinical trials of drugs derived from the marine environment are continuously developing and increasing. One of the most promising area is cancer therapy. Currently, there are two drugs approved by the Food and Drug Administration (FDA) and European Agency for the Evaluation of Medicinal Products (EMA) in cancer treatment, namely Cytarabine (Cytosar-U1®) and Eribulin (E7389 or Halaven®). Trabectedin (ET-743 or Yondelis1®), approved by EMA, is completing key Phase III studies in the U.S. for final approval. It was estimated that 118 marine natural products (MNPs) are currently in preclinical trials, 22 MNPs in clinical trials and 3 MNPs on the market. The characteristics and selectivity profiles of new drugs for cancer therapy, as well as drugs disclosed in related patent applications, will be the focus of this review, providing a brief and ready to use reference.