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This study aimed to measure the axes of colors confusion according to the circadian typology (CT). For this purpose, 28 young male adults aged 20 to 28 participated in this study. The characteristics of the sample were: morning moderately (MM; n = 8; M = 23.25 ± 2.6); Intermediate (I; n = 10; M = 23.30 ± 2.7) and evening moderately (EM; n = 10; M = 23.70 ± 2.5). We used the Pittsburgh Sleep Quality Index (PSQI) and Horne and Ostberg’s questionnaire to ascertain aspects of sleep quality and CT and Cambridge Colour Test (CCT) and the Lanthony Desaturated D-15 Test (D-15d) to verify the color perception. Significant difference was found in the PSQI (F(2.20) = 15.77, p < .001; η2 = 0.62) between EM compared with I (p < .001) and MM (p < .001). We found a difference in the protan confusion axes at 9 a.m. (χ2 = 6.74; p < .05) and 9 p.m. (χ2 = 7.11; p < .05) and deutan at 5 p.m. (χ2 = 11.23, p < .001). The chromatic confusion axes will vary according to the synchronization of daily variation and the EM typology has higher chromatic sensitivity, pointing to a possible relation between visual circadian filters and spatial chromatic information. The daily fluctuation of visual sensitivity may explain the preliminary results on the circadian effects on color perception.

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