Microplastics are small plastic particles less than five millimeters in size. Microplastic is dangerous because it becomes a medium for other pollutants such as heavy metals and harmful bacteria to attach on. This study aims to determine the presence of microplastic in the digestive tracts of fishes in Jakarta Bay. The number of fish samples obtained was 25 fishes consisting of several species, namely, Siganus sp., Albula forsteri, Lutjanus sp., Parastromateus sp., Plicofollis argyropleuron, Pampus argenteus, Paraplotosus albilabris, Sardinella fimbriata, and Platycephalus indicus. The samples were grouped into three categories based on the length of their body, namely small fish with a length of 13-24 cm, medium fish 25-36 cm, and large fish 37-90 cm. The method used to identify microplastics in the fishes digestive tract is optical microscopy. Microplastics were found in 19 fish (76%), those identified as fiber is 73%, identified as films is 18%, and identified as fragment 9%. The larger the size of fish the higher the microplastic content of all types. This implies that microplastic bioaccumulation occurs through the food chain.