Since the Kruithof's work on general illumination, the relationships between correlated color temperatures (CCTs) and human behavior are well documented. In the recent years, because of the high growth of light-emitting diode (LED) lighting products, studies on the effects of LED lighting on human behavior have emerged. This study examines the effects of CCTs on focused and sustained attention under white LED desk lighting. Three CCT conditions (2700, 4300, and 6500 K) are examined, and the Chu Attention Test was used to measure focused and sustained attention. Results show that CCTs affect attention. In specific, the 4300 K condition resulted in a significantly better focused and sustained attention. Comfortableness and clarity are rated by the subjects. The self-reported comfort shows no significant differences among the three conditions, but clarity shows significant differences. Gender differences are also discussed. It is found that the self-reported clarity by males show no significant differences among the three lighting conditions, whereas the self-reported clarity by females is significantly lower when CCT is 2700 K. (c) 2014 Wiley Periodicals, Inc. Col Res Appl, 40, 281-286, 2015