Yingluck, 46, appeared before the National Anti-Corruption Commission (NACC) to defend her against allegations that she as chairperson of the National Rice Policy Committee has failed to address corruption in the scheme that brought her to power in the 2011 election.
"Today she gave 200 pages of evidence to an anti-graft body," her Secretary General Suranand Vejjajiva said.
Yingluck asked the anti-graft body to consider her documents and said she would provide more information if needed.
Thai government started buying rice from farmers at above market prices in 2011 to shore up rural incomes, fulfilling a campaign pledge by the Pheu Thai Party headed by Yingluck.
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The scheme has been widely accused of fuelling rampant corruption.
If found guilty, Yingluck could face removal from office and a five-year ban from politics.
The government had to scramble to raise funds after the farmers decided to march to Bangkok to demand compensation. The NACC has charged the premier of dereliction of duty in approving this rice scheme.