Ledwon, who is not part of Leo Beenhakker's squad currently playing at the UEFA EURO 2008 championships, was discovered at his home in Klagenfurt, Austria by a team-mate, Patrick Wolf.
A spokeswoman for the Austrian club, Iliane Zayic, said: "He was discovered by Patrick Wolf, who had passed by to see him before they were due to go out."
She added: "The club has lost one of its best players, and an irreplacable human being."
The 34-year-old Ledwon, a midfielder, played 18 matches for Poland, scoring one goal. A former player with Bayern Leverkusen in Germany's Bundesliga, he had also acquired a German passport having benefited from double nationality.
He leaves behind a wife and three children.