The current study was carried out to investigate the effect of diazepam treatment on the competitive behavior of male rats and assess the level of anxiety in the competing rats. Forty-four food-deprived rats were individually trained to consume a 50g regular food pellet whose signaled delivery at 30 seconds intervals. The subjects were housed as fixed dyads throughout the study to enhance the establishment of stable dominance hierarchy in the dyads. According to the results of the competition sessions. the twenty-two dyads were classified into 12 stable dyads and 10 unstable dyads One half of each class of dyads was assigned for the anxiety study, while the other half was specified for the competition study Winners and losers were treated with diazepam. 0.5mg/kg. i.p. 30min before testing The anxiometer. LE 3206 control unit was used to assess anxiety level in the animals. The total trial length time was 5 minutes. Diazepam treatment of both stable winners and losers has disrupted the social hierarchy: treatment with diazepam enhanced the competitive behavior of few inhibited animals. In contrast. diazepam treatment could establish a stable dominance ranking in the previously 10 unstable dyads of rats. The Vogel conflict test showed that both winners and losers in different dyads had experienced different levels of anxiety .Treatment with diazepam could enhance the behavior of inhibited animals and it significantly increased the number of shocks received by the stable losers. The anxiolytic effect of diazepam was evident in the unstable dyads. It is concluded that social housing of rats could produce a dominance hlerarchy: this model could induce a state of anxiety in these animals: treatment with an anxiolytic agent could improve their state of anxiety and enhance their competitive behavior.