Abstract: The pollen morphology of six species of aquatic angiosperms from Saudi Arabia belonging to five genera distributed in five families was examined using both light and scanning electron microscopy. Based on apertural type, three distinct pollen types are recognized. Pollen Type-I is characterized by its non-aperturate pollen such as Elodea canadensis, Potamogeton crispus, P. pectinatus and Ruppia maritima. Pollen Type-II is easily recognized by having porate pollen such as Lemna gibba. Pollen Type-III is readily delimited by having colpate pollen such as Myriophyllum spicatum. The correlation between pollen morphology and pollination mechanism is discussed.