<p>Ethyl methanesulfonate (EMS) is a strong alkylating agent commonly used to induce random point mutations, particularly G: C to A: T transitions, by ethylating guanine bases in DNA. Its mutagenic properties, which stem from the transfer of ethyl groups to nucleophilic sites within cells, allow for the creation of various mutant libraries, aiding research in bacterial physiology, metabolism, and antibiotic resistance. This review briefly examines the mechanisms behind EMS mutagenesis and its applications in both forward and reverse genetics. In forward genetics, mutants generated by EMS with altered traits help identify the genetic mutations responsible, while reverse genetics focuses on analyzing specific gene functions. Although there are challenges like mutation stability and reversion, advancements in high-throughput screening methods have improved the effectiveness of EMS mutagenesis. The review also emphasizes the significant impact of EMS-induced bacterial mutants in promoting sustainable agriculture and environmental management. Notable examples include the creation of non-pathogenic <i>Ralstonia solanacearum</i> mutants for controlling bacterial wilt, as well as <i>Bacillus</i> and <i>Pseudomonas</i> mutants that enhance biosurfactant production and bioremediation efforts. Furthermore, EMS mutagenesis has led to the development of stress-tolerant strains that can survive under drought, salinity, and heavy metal conditions, along with strains that improve phosphorus solubilization and nitrogen fixation, contributing to better soil health and plant growth. By connecting fundamental research with practical applications, EMS mutagenesis remains a vital tool for tackling global issues in agriculture, environmental sustainability, and microbial biotechnology.</p>