The main objective for monitoring industrial indirect discharges is the control of compliance of threshold values defmed by water authorities and wastewater system operators and to determine the relevant polluti~n parameters of each industry relevant for tariff calculation. So far, monitoring of indirect industrial discharges executed by water authorities and wastewater system operators is not clearly regulated in Vietnamese legislation. Defining a monitoring strategy, numerous aspects have to be taken into consideration, such as: definition of sampling methods, testing media, parameters to be measures, sampling points, sampling frequency, definition of analytical methods and quality assurance measures, and development and regular update of an indirect discharger cadaster, etc. Surveys in the combined sewer system of Tra Noc Industrial Zone (which is mostly in the form of open channels), located in Can Tho, have shown strong influences of Hau River due to its tidal fluctuations. To some extent the discharged and only partially pre-treated wastewater from industries in Tra Noc is significantly mixed with the river water and diluted in the sewers. However, analysis of relevant parameters, such as BOD, total nitrogen and total phosphorous, out from wastewater grab samples showed that in many cases direct discharge standard QCVN 40:2011/BTNMT (which applies at the moment as Tra Noc Industrial Zone has not a centralized wastewater treatment plant in place, yet) is exceeded significantly.