The organic matter mineralization, decolorization, biodegradability improvement, and toxicity reduction of an industrial cotton dyeing wastewater were investigated. Different treatment approaches, including single and integrated processes, were studied, namely, coagulation/flocculation per se and its combination with Fenton oxidation (approach 1), the Fenton process alone (approach 2) and its integration with either coagulation/flocculation (approach 3) or biological oxidation in a sequential batch reactor (approach 4). All approaches provided a wastewater that meets the Portuguese legislated discharge limits; however, approaches 1 and 3 require smaller operating costs (1.0 (sic)/m(3)) with global removal efficiencies for these two strategies of 70.8% for chemical oxygen demand (COD), 66.1% for dissolved organic carbon (DOC), and 47.6% for biological oxygen demand (BOD5) in approach 1 and 69.2% for COD, 60.4% for BOD5, and 72.4% for DOC in approach 3, along with almost complete color removal in both strategies and toxicity reduction (0.0% inhibition of Vibrio fischeri in the effluent from approach 1). A slight increase of the effluent biodegradability was also observed (BOD5:COD increased from 0.26 to 0.33-0.46, and specific oxygen uptake rate (SOUR) increased from 8.85 to 9.3-11.3 mgO(2)/(g(VSS) h)), depending on the treatment approach. The use of a cheap process (coagulation/flocculation) as pretreatment allowed reducing the amount of reagents needed in the Fenton process, making the latter treatment slightly cheaper and thereby reducing the overall costs.