Oceans have borne most of the biological activities on our planet. A number of biologically active compounds with varying degrees of action, such as anti-tumor, anti-cancer, anti-microtubule, anti-proliferative, cytotoxic, photo protective, as well as antibiotic and antifouling properties, have been isolated to date from marine sources. The marine environment also represents a largely unexplored source for isolation of new microbes (bacteria, fungi, actinomycetes, microalgae-cyanobacteria and diatoms) that are potent producers of bioactive secondary metabolites. Extensive research has been done to unveil the bioactive potential of marine microbes (free living and symbiotic) and the results are amazingly diverse and productive. Bioactive compounds from marine flora and fauna have extensive past and present use in the treatment of many diseases and serve as compounds of interest both in their natural form and as templates for synthetic modification. Several molecules isolated from various marine organisms (microorganisms, algae, fungi, invertebrates, and vertebrates) are currently under study at an advanced stage of clinical trials, some of them have already been marketed as drugs. This article gives an overview of current trends in screening and the activity analysis of metabolites from marine resources. Recent years have seen the introduction into clinical trials of new classes of chemotherapeutic agents, which are derived from marine sources and have novel mechanisms of action. Among other biological activities, the marine ecosystem is increasingly being acknowledged as a source of potential antimicrobial agents. Available treatments for many infectious diseases caused by bacteria, fungi and viruses are limited. Research on new antimicrobial substances must therefore be continued and all possible strategies should be explored. In this review, we will present the structures and antimicrobial activity of natural compounds isolated from marine sources