Cancer is one of the most deadly diseases in the world. Although advances in the field of chemo-preventive and therapeutic medicine have been made regularly over the last ten years, the search for novel anticancer treatments continues. In this field, the marine environment, with its rich variety of organisms, is a largely untapped source of novel compounds with potent antitumor activity. Although many reviews of marine anticancer compounds have been published, we focus here on selected marine compounds that act on the six hallmarks of cancer presented namely self-sufficiency in growth signals, insensitivity to anti-growth signals, evasion of apoptosis, limitless replication, sustained angiogenesis and tissue invasion and metastasis.