Marine natural products, form a field of scientific endeavour, that has recently grown considerably. The isolation, biological evaluation, chemical properties and synthetic elaborations of products of marine organisms have attracted the attention of organic chemists, medicinal chemists, biologists and pharmacists. In this context a structurally and biologically highly interesting class is represented by the marine natural products containing an indole moiety in a pure substituted form or in an anellated form. The present review summarizes primarily the actual results concerning these products as new pharmacologically attractive lead compounds for drug design. The chemistry, biological evaluation and synthetic aspects are discussed. The spectrum of compounds represented comprises simply substituted indoles, peptidic products, dimeric indoles, anellated indoles and a variety of carbazoles. Most of them exhibit significant cytotoxicities.