Abstract Persea americana commonly known as avocado is classified in the flowering plant family ‘Lauraceae’. It is a medicinal plant that serves as both a preventive measure and a cure to several diseases. Ethanol seed extract of Persea americana was studied for in-vitro antioxidant activity and diuretic effect. Different models such as DPPH radical scavenging activity, Nitric oxide scavenging activity and Anti-lipid peroxidation activity were used to determine antioxidant activity. Acute toxicity testing was performed to determine therapeutic dose of the extract using the Litchfeild and Wilcoxon (1949) method using swiss albino mice weighing between 20-25 g. Healthy adult wistar albino rats of both sex weighing 120-180g was used to determine diuretic effect of the ethanol seed extract, volume of urine output was determined using the rat metabolic cages, Na+, K+, Cl– and HCO3– were determined using flame photometric method. Comparisons were made between the control and the different concentration of the extract which includes 500 mg/ml, 250 mg/ml, 125 mg/ml, 62.50 mg/ml, 31.25 mg/ml and they were represented using a one way analysis of variance (ANOVA). The results were expressed as mean± standard deviation using bar charts at P< 0.05 level of significance. Results revealed that ethanol seed extract of Persea americana exhibited its antioxidant activity in a concentration dependent manner, it scavenged DPPH radical by 87.55± 0.63, Nitric oxide radical by 91.44± 0.15, and lipid peroxidation by 75.51± 0.014 all at the dosage of 500mg/ml which is the maximum concentration. Volume of urine and electrolyte Na+, Cl– and K+ was increased significantly when compared to the normal control, HCO3– did not show any significant increase. The results clearly indicate that ethanol seed extract of Persea americana exhibit diuresis and has potential to scavenge free radicals.