The court found Lechkov guilty for signing an unprofitable water and sewerage deal and pressuring a tax official.
The 45-year-old, who was a key figure in the Bulgarian team that reached the 1994 World Cup semi-finals, retired in 1998 and was elected mayor of Sliven, his native town, in 2003. He was re-elected in 2007 and was unsuccessful in seeking a third term in 2011.
He was not immediately available for comment.
Lechkov, who is the Bulgarian Football Union's vice-president, is widely remembered for heading the winner against Germany in the quarter-finals of the 1994 World Cup in the United States.
Lechkov, who played for CSKA Sofia, SV Hamburg, Olympique Marseille and Besiktas, can appeal against the ruling within 15 days.