Plastic has become an important part of our daily life and a vital product in the economic sector because of its wide usage at large scale and is used in all sectors such as agriculture, building, construction, health and in consumer goods as transporting and packing material. A significant amount of plastic is used in television, sound systems, cell phones, computers and office materials, household products, (plastic foam in furniture, plastic chair, kitchen appliances, decoratory products), toys, acrylic composite countertop, sports safety gear, transport, clothing materials, food items, pharmaceuticals, detergents, cosmetics, sanitary wares, tiles, plastic bottles, artificial leather, and likewise. The use of plastic in every sector poses a serious threat to the environment and to all ecosystems. There is an urgent need for a method by which plastic waste can be managed and degraded. The biological techniques are environmentally safe and eco-friendly. Disposal of plastic on both land and marine causes problems for humans, animals, and different life forms. The plastic gets affected by the action of microbes in the natural environment and the microbes have the ability to degrade the plastics and polythene. It is very important to understand the interaction between microbes and plastics. Previous research have revealed that several microbes including bacteria, fungi, actinomycetes, nematodes and arthropods have the capabilities to degrade plastics and polythene. In this chapter we will focus on the basic types of plastics and polythene, their degradation and conversion by different methods. Characterization of bio-degradation is an important part of an ecosystem and circular economy and the factors affecting the bio-degradation of plastics and polythene need more investigation. The microbes possessing different sets of enzyme complexes responsible for natural and commercial degradation of plastic and polythene require their identification, design and production of genetically modified organisms and their characterization.