Nuclear lipid metabolism performs a pivotal function in multiple signaling networks that mediate a variety of cellular events, including proliferation, differentiation and cell survival. The presence of phosphoinositides in the nuclei of mammalian cells is no longer in any doubt, and this has been corroborated by the detection of the enzymes responsible for phosphoinositide metabolism, phosphoinositide kinases and phosphatases in the nucleus. The nuclear phosphoinositide pool exists independently of the cytosolic pool, thereby showing a distinctive feature of nuclear lipid signaling as opposed to its cytosolic counterpart. The principal objective of this review is to summarize our updated knowledge regarding nuclear phosphoinositides and to discuss the current theories about the roles of the nuclear phosphoinositides.