This study was carried out in the Asap Koyan Belaga Sarawak regions of Malaysia where the Orang Ulu ethnics use indigenous knowledge of natural dye extraction from different plant parts. In this region, 51 plant species belonging to 30 families were identified as sources of natural dyes. In natural dye production, different parts of the plant or the whole aboveground plant are used. Eight different colours are gained from the plants. Sometimes the same colour can be obtained from different plants. By combining different plants, it is possible to produce various colours. Plants used by the Orang Ulu ethnics in the dying process are documented, together with their taxonomic characteristics; local names; the colour obtained; purpose and use of natural dye; in addition to which parts of plant are used for producing types of colour.