Essential oils from two species of mint leaves namely Mentha spicata (spearmint) and Mentha piperita (peppermint) were extracted using ethanol as the solvent. The leaves were mechanically cut into three particle sizes of BSS 200, BSS 80 and BSS 40. 200 ml of ethanol was used to extract oil from 40 grams of each particle size sample with a soxhlet extractor. The extraction was carried out at the boiling point of ethanol (78.37oc) for six hours and oil was recovered by boiling off the ethanol. The results obtained showed the yield of oil from Mentha spicata ranged from 12.44% to 38.50%, while Mentha piperita yielded oil ranging from 8.20% to 38.00%. The physio-chemical properties such as specific gravity, acid value, saponification value, peroxide value and iodine value were determined in other to characterise the two oils. The results obtained are as follows; the specific gravities of the oils are 0.935 and 0.862 for Mentha spicata and Mentha piperita respectively, acid values are 0.4769 and 0.4488 mg KOH/g Mentha spicata and Mentha piperita respectively. The saponification values are 93.126 and 86.394 mg KOH/g for Mentha spicata and Mentha piperita respectively, while the peroxide values are 8.50 and 7.0 mEqO2/kg for Mentha spicata and Mentha piperita respectively. The iodine values are 55.20 and 53.93 g I2/100g for Mentha spicata and Mentha piperita respectively. From the results obtained it is observed that the oil extracted from Mentha spicata is denser, and has a higher tendency to be rancid, has lower oxidation stability and higher proportion of unsaturated fatty acids