Antarctic nematode Panagrolaimus davidi has a high cold tolerance. In order to clarify the relationship of this tolerance and the lipid of the nematode, we investigated the phospholipid composition around body surface and the fatty acid composition of surface phospholipids. We also observed the distribution of fat droplets in the nematodes and studied thermal behavior of the total lipids extracted from the nematodes by the use of a differential scanning calorimeter. Around the surface of P. davidi, the ratio of phosphatidylcholine to phosphatidylethanolamine, and the proportion of unsaturated fatty acids were larger than that of C. elegans. Fat droplets exist throughout the body of P. davidi. Thermal studies revealed that triacylglycerol in fat droplets of P. davidi is mostly in a liquid state at the low temperatures around 0℃.