This research aimed to study the dyeing properties on the PLA and silk yarns of the natural dyes obtained from various materials, viz. marigold petals (Tagetes erecta L.), rhubarb rhizomes (Radix et Rhizoma Rhei), garcinia barks (Garcinia Dulcis Kurz), turmeric rhizomes (Curcuma Longa Linn.), sappan barks (Caesalpinia sappan Linn.) and catechu barks (Acacia catechu Willd.). The color properties of the dyed yarns was determined and compared. The results observed the different color properties (L*, a* and b* values) and a shift of λmaxof the dyes on the PLA and silk yarns. This change in color properties of each natural dye was expected to be affected by the types of substrate (textile fiber) and also the chemical nature of the natural dyes. The study of the build-up properties indicated that the turmeric dye is the only natural dye which showed an outstanding performance on PLA and silk. A high degree of color yield of turmeric dye was obtained on both yarns, whereas a poor build-up was observed for the rest of the dyes.