Bioremediation is a biological process that involves the breakdown of contaminants through the utilisation of microorganisms. Bioremediation, a sustainable and eco-friendly approach to environmental restoration, leverages the innate metabolic capabilities of microorganisms to degrade, detoxify, or transform pollutants in various environments. To overcome this obstacle, microorganisms are the most effective choice. Because of the metabolic activity that they employ, microorganisms are able to thrive in any and all of the harsh environments that exist on Earth. Two categories of elements influence the rate of degradation of biological and abiotic environments. Various strategies and procedures are employed globally. Common examples include biostimulation, bioaccumulation, bioventilation, biopiles, and bioattenuation. Case studies of successful bioremediation efforts in oil spills, contaminated soils, and industrial wastewater are examined to demonstrate the practical applications of microbial interventions. This chapter explores the pivotal role microorganisms play in bioremediation, highlighting their significance in addressing diverse pollutants such as hydrocarbons, heavy metals, and pesticides. Microbial species, including bacteria, fungi, and archaea, possess the unique ability to metabolise harmful compounds, either by using them as energy sources or by converting them into less toxic forms. This degradation occurs through various mechanisms, including aerobic and anaerobic respiration, co-metabolism, and enzymatic pathways. Furthermore, the chapter addresses the challenges and limitations of microbial bioremediation, including factors affecting microbial efficacy, such as environmental conditions, genetic adaptability, and the presence of competing organisms.