The relationship between drug use and aggressive behaviour and its consequences on social and financial burden on society is a source of recent concern. This study, therefore, examined the effects of acute exposure to Codeine and Tramadol on aggressive behaviour. Twenty-Eight (28) participants (Female Albino Rats) weighing between 120-150g and 4-6 weeks old, collected from the University of Ibadan Veterinary animal farm were used for this study. They were divided into 5 experimental groups of Codeine, Tramadol, combined Codeine and Tramadol, Control and intruder groups with 6 rats in each group except the intruder group with 4 rats. They were exposed to, 8mg/kg of codeine for the codeine group, 20mg/kg of tramadol for the tramadol group, combined 8mg/kg of codeine and 20mg/kg of tramadol for the combined group, normal saline for the control group and no treatment for the intruder group for 28 days.Â The rats were observed daily after treatment for, biting, dominant posture and scratching as attributes of aggressive behaviour. Randomized block ANOVA showed a significant effect of Codeine and Tramadol on aggressive behaviour among female albino rats, F (3,2010) = 53.53, p < 0.001, Î·2= .07. Female albino rats in the tramadol treatment group significantly exhibited more aggression (x Ì…= 14.08) than control group (x Ì…=11.53) codeine group (x Ì…=11.41) and combined group (x Ì…=7.36). The mean differences were significant (p<.001). It was concluded that chronic exposure to tramadol has implications for aggressive tendencies and combined exposure to tramadol and codeine may be injurious to health.