Venezuelan Attorney General Luisa Ortega Diaz said the aircraft with tail number YV2615, which went missing earlier this year, was discovered overnight near Los Roques archipelago, about 120 miles (190 kilometres) north of Caracas.
The plane was carrying 58-year-old Vittorio Missoni; his longtime companion, Maurizia Castiglioni; two of their Italian friends, and two Venezuelan crew members when it disappeared in the area Jan. 4.
A month later, two pieces of luggage from the plane washed up on the tiny island of Bonaire.
Italy's Foreign Ministry said that the aircraft was found at a depth of 230 feet (70 metres) and had broken into pieces, but that there was certainty it was the Missoni plane because the tail number was legible.
Missoni's family in Italy issued a statement thanking both governments for their support and expressing confidence that an investigation will determine what caused the crash.
"The possible recovery of the aircraft is being evaluated at this moment in Venezuela," the statement said.
It added that the plane was identified on the fifth day of a search thanks to the oceanographic technology of a U.S. ship.
"Now we must float (the wreckage) to be able to identify, establish if the bodies of the people are there," Venezuelan Foreign Minister Elias Jaua told reporters later.
Last week, Venezuelan authorities announced that they had found the undersea remains of another small plane missing since 2008 near Los Roques.
That discovery was made with the help of a U.S. boat that was also going to search for Missoni's plane in the same area.
The Missoni fashion line has continued to show new collections, including menswear summer 2014 over the weekend in Milan as it marks its 60th anniversary, but it has been far from a celebratory year.
Since Missoni's disappearance, his father, Ottavio Missoni, the family-run company's patriarch, died.
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Associated Press writer Colleen Barry in Milan, Italy, contributed to this report.Suggest a correction