Microbes are ubiquitous, survive in all sorts of environments and have a profound influence on the earth. In the present day plant protection scenario, development of resistance to chemical pesticides is the major hurdle in insect pest management. In recent years, several microbes with potential insecticidal properties have come to light. Viruses, bacteria, fungi and protozoa that are known to produce an array of metabolites or toxins, form the basis for microbial insecticides. Since these versatile organisms are amenable for genetic engineering, strains with good insecticidal properties can be identified, evaluated and utilized for pest control. This paper reviews the insecticidal properties of microbes and their potential utility in pest management.