A new colour rendering index, CRI-CAM02UCS, is proposed. It predicts visual results more accurately than the CIE CIR-Ra. It includes two components necessary for predicting colour rendering in one metric: a chromatic adaptation transform and uniform colour space based on the CIE recommended colour appearance model, CIECAM02. The new index gave the same ranks as those of CIE-Ra in the six lamps tested regardless the sample sets used. It was also found that the methods based on the size of colour gamut did not agree with those based on the test-sample method. (c) 2011 Wiley Periodicals, Inc. Col Res Appl, 37, 160-167, 2012; Published online 15 July 2011 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/col.20682