In Iran, wheat straw is produced in huge amount and has been used in animal feed. However, the use of straw as an animal feed is limited due to its low available energy as well as its low nitrogen content. Various chemical delignification methods to improve the digestibility of straw have extensively investigated (Sundstol and Owen, 1984). Biological methods of treating straw using fungi such as white-rot-fungi have also been reported (Zadrazil, 1984). The solid-state fermentation (SSF) of wheat straw with white-rot fungi is a complex process, which is influenced by factors such as the species of fungus, substrate, temperature and moisture (Zadrazil, 1984). Rouzbehan et al., (2000) noted that pre-treating the straw with urea and incubation with either pleurotus ostreatus or pleurotus Persian fungi has improved the digestibility of wheat straw. In this study, the effect of urea and another two species of white rot fungi on the nutritive value of wheat straw was tested.