In this study, the CIE whiteness (CIE WI) and whiteness tint (Tw) of optically whitened (OWA) woven (plain and twill) polyester fabrics irradiated with xenon arc light were investigated. The fabrics were whitened in four concentrations using nine different commercial optical whitening agents, and were irradiated with xenon arc light under specific conditions between 0 and 100 h at 10-h intervals. The reflectance of the OWA fabrics was measured by using spectrophotometer, whereas the CIE WI and Tw values were calculated by using computer software. The results were investigated by statistical methods using analysis of variance and regression curves in which of the CIE WI of OWA polyester fabrics was found to decrease, while the Tw was also affected depending on irradiation time from the xenon arc light. (c) 2011 Wiley Periodicals, Inc. Col Res Appl, 2013