The genetic apparatus of the eukaryotic cells is enclosed by the nuclear envelope, which consists of two membranes, the inner and the outer ones, and can be regarded as the specific part of the endoplasmatic reticulum of the cell. There are nuclear pores in the nuclear membranes--complexes, which provide the highly selective transport of macromolecules and passive transport of ions and small molecules. Besides, ion channels selective to cations and anions were described in the inner and the outer nuclear membranes. The physiological significance of these channels is not still clear because of the difficulty of access for the direct electrophysiological investigation, but we can suppose that they can play an important role in the ion balance between the cytoplasm/nucleoplasm and the nuclear lumen. In this review we gathered and analyzed data about spontaneously active ion channels which were found in the membranes of the nuclear envelope from cells of different types and tried to propose their functional meaning.