Mortierella alpina is known as an arachidonic acid (AA) producing oleaginous fungus. Extraction of lipids from wet and dry M. alpina biomass was compared. Lipids yield of extraction from dry cells was higher than that of extraction from wet. Wet extraction mainly extracted lipid bodies and lipids in membranes did not extract effectively. Enrichment of AA from the fungal lipids by a urea inclusion method was studied. Most of the saturated and monounsaturated fatty acids, 93.0% and 84.6%, respectively, were removed by forming urea inclusion compounds. AA was concentrated after urea inclusion. Its content in total fatty acids increased 6.2-folds and reached 57.1% with a recovery of 81.9%.