The Associated Press reported that a jury deliberated for 19 hours before returning guilty verdicts Wednesday against DeLay on money laundering charges. He faces up to life in prison.
"This is an abuse of power. It's a miscarriage of justice, and I still maintain that I am innocent. The criminalization of politics undermines our very system and I'm very disappointed in the outcome," DeLay told reporters outside the courtroom.
Prosecutors said DeLay, a Texas Republican who once held the No. 2 job in the U.S. House of Representatives, used his political action committee to illegally channel $190,000 in corporate donations into 2002 Texas legislative races through a money swap.
DeLay, who appeared on Dancing with the Stars last year, said he did nothing wrong.
The verdict came after a three-week trial in which prosecutors presented more than 30 witnesses and volumes of e-mails and other documents. DeLay's lawyers presented five witnesses.