Natural compounds have received much attention and research in recent years since the industrial economy developed. Essential oils, which contain many volatile constituents and aromatic compounds, have been around for a long time but are still considered to this day thanks to their natural properties and their unique application. There are several ways of collecting essential oils from herbal plants, including ancient approaches to contemporary techniques using different sections of plants such as buds, vegetables and nuts. In this study, the leaves of Kaffir lime (Citrus hystrix) were used to investigate the yield of essential oil extracted by the classical distillation system (hydro-distillation). The obtained essential oil was then analyzed for the chemical composition by gas chromatography–mass spectrometry (GC-MS). A total of 100 g of Kaffir lime leaves, under the following conditions: 1:3 of ratio of material to water, 120 C of the temperature within 60 min. The extraction process yielded 1.3 mL of essential oils. GC-MS analysis also identified 16 compounds in the essential oil, accounting for 99.99% of total oils. The main compounds included citronellal (85.4%), citronellol (6.8%), linalool (1.9 %), citronellyl acetate (1.7%), and other compounds with content less than 1.0% by hydrodistillation. The findings of chemical composition of Kaffir lime leaves EO suggest further studies on optimization the extraction process for a desirable phytochemical content.