Ethylene, a gaseous phytohormone, plays a pivotal role in influencing plant growth, development, ripening, and senescence, as well as responses to various stresses and pathogen infections. This crucial phytohormone is synthesized from S-adenosylmethionine (SAM) through the intermediate 1-aminocyclopropane-1-carboxylic acid (ACC). In this chapter, we will delve into the techniques, materials, and methods for measuring internal and external ethylene concentrations in fruits and vegetables, both at the time of harvest and during storage, using gas chromatography (GC). Furthermore, it is essential to recognize that fruits and vegetables can be categorized based on their response to ethylene and their respiration patterns, distinguishing them as climacteric or non-climacteric. These protocols hold significant importance, as they enable us to identify the optimal maturity stage for fruits and vegetables, whether for short-term or long-term storage. This, in turn, helps extend the longevity and shelf life of these perishable crops.