Suzuki, who won 500cc world titles with the likes of Briton Barry Sheene, and Americans Kevin Schwantz and Kenny Roberts Jr, pulled out in 2011 saying they needed to reduce costs in the face of a global economic downturn.
They said at the time that they hoped to return in 2014.
The manufacturer joined an official MotoGP test at Barcelona's Circuit de Catalunya on Monday and said in a statement that they would continue to test inside and outside Japan after that.
"Suzuki Motor Corporation will participate again in MotoGP racing from 2015," it added.
Italian Davide Brivio, Valentino Rossi's former boss at Yamaha, will manage the test team with Frenchman Randy De Puniet serving as their development rider on the 1,000cc machine.
Suzuki's return will give MotoGP at least four major manufacturers in the top category, with Honda, Yamaha and Ducati all present. Kawasaki pulled out in 2009.
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- Kenny Roberts Jr
- Barry Sheene