Abstract: The effect of gasoline vapours (17.8±2.6 cm3/h/m3/day) on renal functions was assessed from the total kidney weights and the levels of serum creatinine, urea and blood urea nitrogen (BUN) in male and female rats, following 64 days of exposure. The results showed an insignificant (p>0.05) increase in percentage kidney weight per total body weight (PKW/BW), decrease in total serum protein and a significant increase (p<0.05) in serum creatinine, urea and BUN levels in both male and female test rats, compared respectively with the control. However, the percentage changes in the PKW/BW, serum creatinine and urea levels obtained for female rats were observed to be significantly higher (p<0.05), compared to the respective percentage changes obtained for male rats. This observation indicates that frequent exposure to gasoline vapours may cause renal dysfunction in rats, with females at greater risk.