The effects of aqueous extract of Ocimum gratissimum on transaminases activity of albino rat were investigated. The objective was to evaluate the effects of aqueous extracts of fresh leaves of Ocimum gratissimum on transaminases activities in albino rats. Sixteen albino rats were randomly assigned to four experimental groups of 4 marked as control group, groups A, B, and C respectively. Groups A, B and C were treated with oral administration of aqueous extract of Ocimum gratissimum at 100mg, 200mg and 400mg/kg body weight daily respectively for two weeks. Control group received no treatment. Results showed that treatment of rats with the respective doses of the extract did not significantly alter the serum and liver levels of ALT and AST in all test groups. There was a significant increase in the activities (P<0.05) of AST and ALT in the kidney and the serum which might be caused by activation of enzymes synthesis in renal cells. The result suggests that ingestion of aqueous extract of Ocimum gratissimum could confer protection on the liver tissues against injury, damage or disease and the extract may not be toxic at the doses investigated.