Male New Zealand white rabbits were used to investigate the effect of two levels of isoflavones on the growth performance, nutrients digestibility, N-balance and caecal microbial activity.  The experimental rabbits were randomly divided into three groups (n=5/group). The first group was used as a control, while groups 2 and 3 were given orally isoflavones at 2.5 (low dose, LD) and 5.0 (high dose, HD) mg/Kg body weight (BW), respectively. Doses of isoflavones were orally given to the animals every other day for 13 weeks.           The results showed that the LD (2.5 mg) of isoflavones increased feed intake, but there was no significant difference in water intake. Moreover, supplementing 2.5 mg of isoflavones improved the digestibility of all nutrients and total digestible nutrients (TDN) and digestible crude protein (DCP). On the other hand, isoflavones at 5.0 mg improved the digestibility of dry matter (DM), crude protein (CP) and ether extract (EE) only. Nitrogen balance increased by 27% in 2.5 mg- treated rabbits over the control. Supplementation of isoflavones slightly decreased the VFA with no effect on ammonia- N concentration in the caecum. This study concluded that isoflavones have a favorable effect on growth performance therefore, the animal^, s diet must contain an adequate level of soybean meal, which covers the isoflavones requirements.