Ethylene at a low concentration is essential for the germination of seeds and the development of seedlings in the plant species. However, the same ethylene at a higher concentration inhibits the elongation of roots, seed germination, and seedling development. In plants, 1-aminocyclopropane-1-carboxylic acid (ACC) serves as the direct precursor for the production of ethylene. The enzyme ACC deaminase produced by certain bacteria plays a pivotal role in reducing ethylene levels in plants by breaking down ACC into α-ketobutyrate and ammonia, thus positively influencing various physiological processes. Bacteria can utilize these compounds for their own growth and development. This chapter provides a comprehensive overview of quantitative as well as qualitative methods including colorimetric assay, solid plate, and PCR-based assays for readily screening unknown ACC deaminase–producing bacterial strains.