About 200 supernova remnants have been found in the galaxy(1), six of which are younger than about 1,000 years (ref, 2), Observations of these young remnants are important for understanding of the late phases of supernova evolution, and each new object should add substantially to our knowledge of the processes involved. Here I report the discovery of a supernova remnant (RX J0852.0 - 4622), identified by its X-ray emission, at the southeast corner of the known Vela supernova remnant. The high temperature (>3 x 10(7) K) indicates an age of less than similar to 1,500 yr. The observed diameter of the remnant is about 2 degrees, which suggests a distance of less than 1 kpc, based on a comparison with the remnant of the supernova of AD 1006. RX J0852.0 - 4622 may therefore be the nearest supernova to have occurred during recent human history.