The science team sifting data from the US space agency's (Nasa) Kepler telescope says it has identified 715 new planets beyond our Solar System.
This is a huge new haul.
In the nearly two decades since the first so-called exoplanet was discovered, researchers had claimed the detection of just over 1,000 new worlds.
Kepler's latest bounty are all in multi-planet systems; they orbit only 305 stars.
The vast majority, 95%, are smaller than our Neptune, which is four times the radius of the Earth.
Four of the new planets are less than 2.5 times the radius of Earth, and they orbit their host suns in the "habitable zone" - the region around a star where water can keep a liquid state.
Whether that is the case on these planets cannot be known for sure - Kepler's targets are hundreds of light-years in the distance, and this is too far away for very detailed investigation.
The Kepler space telescope was launched in 2009 on a $600m (£360m) mission to assess the likely population of Earth-sized planets in our Milky Way Galaxy.
Faulty pointing mechanisms eventually blunted its abilities last year, but not before it had identified thousands of possible, or "candidate", worlds in a patch of sky in the constellations Cygnus and Lyra.
It did this by looking for transits - the periodic dips in light that occur when planets move across the faces of stars.
Before Wednesday, the Kepler spacecraft had confirmed the existence of 246 exoplanets. It has now pushed this number up to 961. That is more than half of all the discoveries made in the field over the past 20 years.
"This is the largest windfall of planets that's ever been announced at one time," said Douglas Hudgins from Nasa's astrophysics division.
"Second, these results establish that planetary systems with multiple planets around one star, like our own Solar System, are in fact common ( via bbc.co.uk ).