Phospholipase D (phosphatidylcholine-phosphatidohydrolase, EC 3.1.4.4) hydrolyses lecithin into phosphatidic acid and choline. A review is given on the properties of phospholipase D described in the literature; it deals with the occurrence and distribution of phospholipase D in higher plants, with it's pH and temperature, substrate specifity, activators, inhibitors and with occurrence and properties of bacterial phospholipase D.