Carpet printing wastewater (CPW) was spiked with metal-complex dyes at concentrations of 10 and 30 mg/L to investigate the effect of feed color on separation performance of nanofiltration (NF). The rejection was excellent; 98-100% for color and COD under all spiking conditions. Although the flux decline increased with increasing dye concentration, the concentration polarization was the main cause of the flux decline. The effect of surfactants on NF separation performance was also investigated by preparing synthetic wastewaters with dyes and auxiliary chemicals. The presence of a non-ionic penetrant did not adversely affect the color rejection whereas the COD rejection was reduced from 100% to 91%. Furthermore, fouling became dominant when surfactants were used.