Reports say that the two people on board were found dead.
A Super Puma helicopter, Navy vessels, a Frontex vessel, and private vessels are taking part in the search.
A Cessna-type aircraft has gone missing in the area near the island of Samos.
According to initial reports, the small aircraft was operating a leased flight from Israel and encountered a problem while trying to approach Samos airport. It is unknown at this point how many were on board.
When it failed to land due to a hitherto unknown problem, the airport authorities sounded the alarm and mobilised the port police and fire brigade.
A search operation is in progress.