The research focuses on the technologically plain and inexpensive procedure of impregnation dyeing of spun yarn with photoluminescent pigment Special lux TPLL-9E Yellow-Green (Special Chem, Italy). The pigment concentration was 50 and 150 g of pigment per kilogram of yam and two binding agents were used, i.e. Elastil Transparent FG (Minerva, Italy) and Padding Binder FM/N (Minerva, Italy), as well as a mixture of both. The impregnated coating was conducted on yarns with linear density Nm 125/1 and Nm 20/1, where the mixture ratio of cotton/polyester was 50/50 and 67/33. The luminance measurements were made on the unwashed, once washed and five times washed yams. In some cases, a high luminance level of yarns up to 500 mcd/m2 was measured, which decreased only slightly after one wash, and after five washes, it dropped to 230 mcd/m2. In accordance with the expectations, the luminescence decreased exponentially with time; however, the yams could still be noticed in the darkness even after 12 hours.