Marine invertebrates produce a large number of unique and structurally diversified natural products which represent a major source of bioactive molecules particularly for pharmaceuticals leads. This great potential has elicited worldwide scientific and economic interests in searching novel drugs from marine invertebrates since de pioneering work of Bergmann on sponge nucleosides in 19501,2. These efforts have resulted in several thousands of novel marine natural products exhibiting a wide range of bioactivities such as anticancer, antiviral, antifungal and antibacterial properties. Today, the pioneering countries in marine natural products discovery (USA, Japan, Australia, Spain…) are benefiting from the great potential commercial and social value of such a research. Since the early 1990s, the Chemistry Laboratory of Natural Substances and Food Sciences (LCSNSA, University of La Reunion) has been trying to gain a foothold in this field of research. The laboratory, located at Reunion Island, occupies a strategic location. Indeed, with a series of islands scattered in the western Indian Ocean along the southeast coast of Africa (Madagascar, Seychelles, the Comoros, Mayotte, Mauritius, Eparses islands), Reunion Island belongs to a global biodiversity hotspot. And despite the intense global interest in marine natural products, the chemistry of marine fauna of this part of the World remained largely ignored. This communication will therefore provide an outline of the contribution made by the LCSNSA to marine natural products research in the west part of Indian Ocean. Over the last fifteen years, our research programs were more precisely concentrated on marine invertebrates from Reunion Island, Mayotte and Madagascar. Among the numerous marine invertebrates encountered in these areas, sponges, ascidians and soft corals have predominated in all our collection expeditions and have therefore received special attention from our research group. More than one hundred new compounds showing relevant bioactivity, were isolated.