In order to investigate the effects of locally grown red pepper on egg-yolk colour and egg production in laying hens, twelve diets based on white corn and wheat grain were supplemented by various amounts of red pepper and artificial colouring pigments, and offered to 96 layer hens for 13 weeks from the beginning of the laying circle. The characteristics of egg production and egg-yolk colour were examined under the influence of dietary treatments. The present results showed that egg weight, daily feed intake and egg yield did not significantly differ between the experimental diets, indicating that red chilli can be used as an alternative feed ingredient in layer diet with no significant alterations in the bird performance. Furthermore, the highest colour pigmentation were obtained from the diets (wheat + yellow corn) with 3.0 and 4.0% red chilli added whereas the lowest colour pigmentation was obtained from the diets (white corn + no wheat) with no chilli or artificial pigments. The most preferred colour pigmentation by the customer was obtained from the diets of 25% yellow corn and 32.4% wheat to which 0.5% red chilli added. Increasing amount of the red chilli in the yellow corn and wheat based diets resulted in an increasing reddish colour pigmentation of egg-yolk. On the other hand, we could not measure the colour of pigmentation by RCF scale of the diets containing only white corn (around 55%) in which the amount of the red chilli ranged from 2.0 to 4.0%. The addition of 0.30 and 0.25% artificial pigments to the diets of white corn and the diets of yellow corn + wheat resulted in optimum colour pigmentation. Although we did not test the interaction effects between the artificial pigments and red chilli on the egg-yolk colour pigmentation, the results suggested that an appropriate combination of artificial and natural colour pigments can be used to obtain optimum egg-yolk colour pigmentation. In short, the red chilli of 4th harvest, which is not suitable for human consumption, did not adversely alter the laying performance, and additionally the use of red chilli as a potential natural colour pigment caused to an optimum egg-yolk colour, especially at the rate of 0.5% in the layer diet. © Asian Network for Scientific Information 2003.