The yield of leptospiral LPS was able to increase 1-2 times when the cells were treated with EDTA-Na before extracting with hot phenal-water method. The colours and solubility of L-LPS were improved. When the leptospiral cells were stored for a long period of time, and treated by EDTA-Na, the phase distribution of the LPS changed, i.e. they returned from water phase into phenol phase. Such change was related to the quantity of both the saccharide and lipid.