SEVERAL authors have suggested that the phospholipids may participate in the absorption of fats1-3. However, an examination of the 32P turnover in the phospholipids of the mucosa of dogs and rats led Zilversmit et al.4,5 to conclude that these compounds are of little significance in this process. More recently, from the results of 32P-turn-over in experiments with everted intestinal sacs of golden hamsters, Johnston and Bearden6 have suggested that the phosphatidic acid might be an intermediate in the transport of fatty acids during absorption. But these claims could not be confirmed by Gurr et al.7, who studied the 32P turnover of the intestinal phospholipids of living rats. It is clear that in all these experiments labelled 32P was used and no attempt was made to investigate the uptake of free fatty acids by the mucosal phospholipids; we have found that the mucosal phospholipids rapidly take up the free fatty acid from the lumen of the small intestine.