The article reviews the current state and future prospects of microbial toxicity tests, which are widely used in various scientific and technical fields, particularly in the risk assessment of chemical compounds in the environment. The focus is on standardized ISO and OECD methods, including both standardized and non-standardized tests, and their applications in predicting effects in natural and technical aqueous compartments. The review highlights the importance of microbial toxicity tests in biodegradation tests and their role in characterizing inocula used in biodegradation processes. Key points include the sensitivity and applicability of different tests, the integration of microbial toxicity tests with ecotoxicity tests, and the development of a new concept called the Physiological Potential of an Inoculum (PPI), which combines chemical resistance potential (CRP) and biodegradation adaptation potential (BAP). The article also discusses the limitations and advantages of these tests, emphasizing the need for standardized methods and the importance of selecting appropriate inocula for accurate predictions.The article reviews the current state and future prospects of microbial toxicity tests, which are widely used in various scientific and technical fields, particularly in the risk assessment of chemical compounds in the environment. The focus is on standardized ISO and OECD methods, including both standardized and non-standardized tests, and their applications in predicting effects in natural and technical aqueous compartments. The review highlights the importance of microbial toxicity tests in biodegradation tests and their role in characterizing inocula used in biodegradation processes. Key points include the sensitivity and applicability of different tests, the integration of microbial toxicity tests with ecotoxicity tests, and the development of a new concept called the Physiological Potential of an Inoculum (PPI), which combines chemical resistance potential (CRP) and biodegradation adaptation potential (BAP). The article also discusses the limitations and advantages of these tests, emphasizing the need for standardized methods and the importance of selecting appropriate inocula for accurate predictions.