Crude oil, a major source of energy, is being exploited as a driver of the economy throughout the world. Being a limited resource, the price of crude oil increases constantly and the exploitation of mature reservoirs becomes essential in order to meet the ever-increasing energy demands. As conventional recovery methods are not sufficient to fulfil the growing needs, there is an incessant demand for developing new technologies which can help in efficient tertiary recovery in old reservoirs. Petroleum biotechnology has been emerging as a branch that can provide solutions to major problems in the oil industry, including increasing oil production from marginal oil wells. The enhanced oil recovery (EOR) method comprises four methods – chemical, thermal, miscible, and immiscible gas flooding – as well as microbial interference to increase recovery of the remaining hydrocarbons trapped in reservoir rocks. Biochemically enhanced oil recovery comprises an array of blooming technologies for tertiary oil recovery methods which is eco-friendly, cost-effective, and efficient in extracting the residual oil trapped in reservoir rocks. Biochemical enhanced oil recovery (BcEOR) is based on the principle of using biochemical by-products produced by microbial species to enhance oil recovery, etc. All these technologies work on the principles of reducing viscosity, increasing permeability, modifying solid surfaces, emulsifying through adherence to hydrocarbons, and lowering interfacial tension. BcEOR technologies either employ the beneficial microorganism itself or the biochemical by-products produced by the microbial species to enhance tertiary oil recovery. This review paper discusses the chronological development of biologically enhanced oil recovery and its various mechanisms.