Neptunia Oleracea is locally known as Pucuk Setangki (Water Mimosa) that belongs to the Fabaceae family which is a herbal plant that is believed originated from India, Southeastern Asia and Tropical Africa. It is commonly known for its benefits as first aid medicine and food ingredients. Usually, Water Mimosa is used in the traditional medicines of Malaysia. It is part of treatments for earaches and even syphilis. It is also used as food ingredients such as masak lemak cili api (cook chili fat). Nowadays, people tend to use modern medicine that they have forgotten about the traditional herbs that our ancestors used. Thus, the goal of this research is to analyze the functional group of Neptunia Oleracea extract. Specifically, the research will focus on the functional group that is in the pucuk setangki. It can also increase people's knowledge of pucuk setangki and encourage them to use it more often. In order to prove its efficacy, functional group analysis of Neptunia Oleracea leaf extract was performed using Fourier Transform Infrared (FTIR). The spectrum and wavelength obtained can be used to identify the functional group and thus, the antimicrobial compound was discovered present in the plant. Based on this study, Neptunia Oleracea leaves do have antimicrobial compounds. Specifically, the research will focus on the functional group in the pucuk setangki. This research reminds people of the importance of pucuk setangki and its properties. This research is a contribution for other researchers to make other products based on this research and to help others to realize the benefits in pucuk setangki. The result will be shared throughout people so it can be use by people in the future.