This review provides an overview of the microbial degradation of polycyclic aromatic hydrocarbons (PAHs), a class of hazardous organic compounds consisting of three or more fused benzene rings. PAHs are primarily derived from fossil fuel combustion, industrial processes, and food cooking. They are highly persistent in ecosystems due to their low water solubility and can accumulate in sediments, leading to bioaccumulation and potential health risks. The degradation of PAHs is primarily driven by a diverse microbial community, including bacteria, fungi, and algae, which metabolize these compounds through various pathways. Molecular oxygen is essential for the initial hydroxylation of PAHs by microorganisms. Fungi use hydroxylation as a prelude to detoxification rather than catabolism. The review also discusses the relationship between the chemical structure of PAHs and their biodegradation rates in aquatic and terrestrial ecosystems, highlighting the importance of microbial degradation in decontaminating sediments and surface soils.This review provides an overview of the microbial degradation of polycyclic aromatic hydrocarbons (PAHs), a class of hazardous organic compounds consisting of three or more fused benzene rings. PAHs are primarily derived from fossil fuel combustion, industrial processes, and food cooking. They are highly persistent in ecosystems due to their low water solubility and can accumulate in sediments, leading to bioaccumulation and potential health risks. The degradation of PAHs is primarily driven by a diverse microbial community, including bacteria, fungi, and algae, which metabolize these compounds through various pathways. Molecular oxygen is essential for the initial hydroxylation of PAHs by microorganisms. Fungi use hydroxylation as a prelude to detoxification rather than catabolism. The review also discusses the relationship between the chemical structure of PAHs and their biodegradation rates in aquatic and terrestrial ecosystems, highlighting the importance of microbial degradation in decontaminating sediments and surface soils.