Lipids from Chlorella vulgaris were successfully extracted using an ionic liquid, BmimMeSO₄. BmimMeSO₄ dissolved C. vulgaris, leaving the lipids insoluble. The undissolved lipids could easily be recovered due to the lower density of the lipid phase. Furthermore, ultrasound irradiation highly enhanced the extraction rate and yield with BmimMeSO₄. The total amounts of lipid extracted from C. vulgaris by the Soxhlet method and the Bligh and Dyer's method were 21 and 29 mg/g dry cell weight (DCW), respectively, whereas it was 47 mg/g DCW with BmimMeSO₄. Additionally, the amount of lipid extracted using BmimMeSO₄ was 1.6 times greater with ultrasound irradiation. The rate of extraction of lipids from C. vulgaris with BmimMeSO₄ was also 2.7 times greater with ultrasound irradiation. The fatty acid profiles of the lipids extracted using BmimMeSO₄ were very similar to those of the lipids obtained by Bligh and Dyer's method.