The painting was stolen in May 1987, when a thief smashed his way into the museum with a sledgehammer during the night.
The theft was reported to both Interpol and the Art Loss Register – the world's largest international private database of stolen, missing and looted artwork.
The painting's recovery
The painting was recovered after an art dealer in Britain checked with the Register before selling the Matisse.
"We are happy the painting seems to be okay and in good condition," Ek said. "It was a good start to the New Year."
Marinello would not give details of how he got hold of the Matisse.
"No arms were broken and no payments were made," he said, adding the painting would be returned to the museum through Sweden's ministry of culture.
The Moderna Museet is still missing a painting by Georges Braque, after a theft in 1993.
Stolen art is a lucrative industry with $6- to 7-billion worth of thefts every year, and the current global economic downturn has led to a surge in crimes, according to Marinello.
Last year, for example, thieves made off with paintings by Picasso, Matisse, Monet and other prominent modern artists from Rotterdam's Kunsthal museum worth tens of millions of dollars.
If thieves cannot collect a ransom from insurers or owners, the art is sold on the black market, often for a fraction of its real worth, or even exchanged for drugs or guns.
Of the 360 000 objects on the Register's database, Marinello said there were several he particularly wanted to find.
The first is a hoard including paintings by Vermeer, Degas and Rembrandt worth $300-million stolen from the Isabella Stewart Gardner Museum in Boston in 1990.
There is a $5-million reward for the paintings.
"Then there is a Rafael stolen by the Nazis in WWII that is pretty nice," he said.
Marinello, however, will have his work cut out. By his admission, only 5-10% of stolen art is ever recovered. – Reuters