The ZnO nanoparticles (ZnO NPs) were synthesized by co-precipitating method followed by calcining at 500 o C for 4 h. The characterization data show that the synthesized ZnO NPs were present in hexagonal wurtzite structure and space group P63mc with high purity and good crystalline nature. The synthesized ZnO NPs were tested for decolorization of congo red (CR) dye under microwave irradiation using microwave induced catalytic (MIC) method. The investigation results showed that the microwave induced ZnO NPs process could effectively decolorize the CR dye with the efficiency approaches 90.63% in a short contact time under given condition of 10 mg/l CR dye, 300 watt of microwave power, 3 min of contact time, and 3 g/l of catalyst dosage. Since the microwave-induced catalytic process in this study is noticeable, the microwave technology coupled with ZnO NPs as catalyst may have synergistic effects on the decolorization of CR dye giving high degradation ratio in short reaction time. Therefore, the microwave technology can be used as an alternative option to enhance the catalytic activity of metal nanoparticles dealing with removal of various industrial dyes containing wastewater.