This study aims at assessing the variation of water quality in regions affected by industrial production activities in An Giang province, Vietnam. Seven surface water quality parameters including temperature, pH, total suspended solids (TSS), biological oxygen demand (BOD), chemical oxygen demand (COD), ammonium (NH₄⁺), and coliform were used for the assessment. The water samples were taken at three locations in the rivers influenced by industrial clusters three times per year (March, June and September). The results show that the water quality parameters including TSS, BOD, COD, NH₄⁺ exceeded the limits of column A1 of the national regulations on surface water quality (QCVN 08-MT:2015/BTNMT). In addition, the water is heavily microbially contaminated since coliform density exceeded the limits by 3 to 18.4 times. The water quality index (WQI) ranges from 15 to 72 indicating the overall water quality from moderate to poor. The dry season is the most polluted time, especially at My Quy industrial park (CN1). In the rainy season, the water quality improves although pollution still occurs. The main causes can be not only industrial activity but agricultural production activities, domestic wastewater services, circulation processes since the collected water samples have been polluted by several integrated polluting sources.