The investigation on bio-colour production for use is food through fermentation and evaluation of the yellow pigments secreted by Thermomyces sp in submerged culture, using sucrose and ammonium sulphate as carbon and nitrogen sources is reported. After extraction and purification, these colorants were suspended in

water for evaluation. The stability of the extract was tested in different environmental conditions such as pH, heat, light, antioxidants and chemical preservatives. It has been shown that increasing the pH, temperature or exposure to light does not affect stability of the yellow pigment. The pigment extract was more stable at pH 5.1 and 8.0, temperature at 10^OC, 20^OC and 30^OC both in the presence and absence of light, however moderate stability was observed in antioxidants and preservatives. Thus, yellow pigment obtained fromThermomyces sp has a high potential to be used as a natural food colorant.