This study aims to investigate the color changes of Naturally Colored Organic Cotton (NaCOC) fibers after scouring, and to evaluate the human sensory perception for the fibers. Furthermore, it tries to observe the relationship between the color coordinates and the sensory perception. Three colors (ivory, coyote-brown, green) of NaCOC fibers were scoured under four different treatments (boiling water, enzyme, sodium carbonate, sodium hydroxide). The color coordinates (L, a, b) were measured in CIELAB using spectrophotometer (SP62, X-Rite), and color differences (${Delta}L$, ${Delta}a$, ${Delta}b$, ${Delta}E$) were calculated. Human sensory perception for the NaCOCs was evaluated by 27 female participants. The questionnaire consisted of nine pairs of bipolar visual sensory adjectives using the SDS. The values of L and b fell, while the value of a arose after scouring in general. The value of ${Delta}E$ was the highest when treated with alkali solutions among all treatments. Human sensory perception such as brightness, clearness, lightness and freshness generally decreased, while vividness and strength increased. The meaningful color factors to predict brightness, lightness were L and ${Delta}L$, and those to predict vividness and strength sensory were ${Delta}L$.