The WEsterbork Northern Sky Survey (WENSS) is a large–sky survey being carried out at 92 and 49 cm with the Westerbork Synthesis Radio Telescope (WSRT). At 92 cm WENSS will cover the sky north of declination +30° (an area of 10,000 square degrees) to a limiting (5σ) flux density of about 15-20 mJy. Both linear and circular polarization data is obtained. The polarization images have a noise level of about 2 mJy (lσ). The spatial resolution at 92 cm is about 1′. At 49 cm about one fifth of this area will be covered to somewhat lower flux density and with twice the resolution. The resulting catalogue will contain about 250,000 sources at 92 cm and 30,000 sources at 49 cm.