Citarum River is a large river located in West Java Province. The current condition of the Citarum River is highly polluted, especially in urban areas. Utilization of river water quality models is one of the popular methods to support river recovery. The deoxygenation rate is an important coefficient in the BOD-DO formula used in the water quality model. Usually, the deoxygenation rate is determined in laboratory in short term. A long term technique of laboratory test will likely gives better results. This study aims to determine the actual coefficient of the deoxygenation rate of the Citarum River water by using the long term technique. Sampling was carried out at 2 points which were considered to be able to represent the condition of the Citarum River. The laboratory analysis method used in the calculation of the deoxygenation rate uses the Thomas’ Slope Method and the empirical formula of Hydroscience. The results showed the value of the deoxygenation rate range using the Slope method as a whole that ranged from 0.33 to 0.56 per day. While the value of the deoxygenation rate ranges using the Empirical formula ranges from 0.37 to 0.46 per day. The overall BOD (La) range ranges from 44.03 to 55.03 mg/L. The value of the deoxygenation rate obtained from the long term technique give similar range to that of empirical formula result. It suggests that the long-term technique can improve the results of the short-term deoxygenation rate method.