Spider silk is categorized as fibrous protein. Spiders produce several types of silk. Spider silk is important because of its maximum mechanical strength, biocompatibility and biodegradability, pore filling ability and very low immunogenicity. In this review structure and types of silk producing gland, spinning process, chemistry of spider silk fiber, mechanical properties and applications of silk in health, military industry and many other fields is discussed. Its antifungal and antimicrobial potentials are also explored. Researchers are trying to introduce advanced methods to manufacture spider silk artificially to enhance silk production. Silk fiber can be designed after determining type and sequence of constituent amino acid or by inserting silk producing gene in another suitable animal.