Campaigners had long accused Aaron Ringera of not doing enough
Kenya's much-criticised anti-corruption chief has resigned just weeks after he was reappointed by the president.
Aaron Ringera said he was stepping down in the best interests of the country and the anti-corruption commission.
President Mwai Kibaki had unilaterally reappointed him for a second five-year term as head of the commission without consulting parliament.
MPs refused to accept the appointment, saying Mr Ringera was ineffective and that the president had acted illegally.
Correspondents say Mr Ringera has come under fire from Kenyans for not doing enough to tackle corruption.
The KACC head is Kenya's best-paid civil servant, earning 2.5m shillings ($34,000; £21,000) a month - a higher salary than the president.
Mr Kibaki reappointed Mr Ringera without consulting MPs earlier this month, immediately sparking protests from politicians and anti-corruption campaigners.
Aid donors accused the president of failing to keep his promises to tackle the rampant corruption in Kenya.
Since Mr Kibaki took office in 2002, no senior officials have been convicted.
But at a press conference, Mr Ringera defended his record, saying he did not have the powers to prosecute those accused of corruption.
He said the commission had investigated and recommended the prosecution of eight government ministers, four MPs, 11 permanent secretaries and 65 directors or chief executive officers of public institutions, Reuters news agency reports.
Assets worth $60m (£37m) had also been recovered, he said.
"Experience has shown that those commissions with powers to investigate and prosecute their own cases have done better than those without," he said.
The BBC's Anne Waithera in Nairobi says when parliament voted to block Mr Ringera's reappointment it was the first time in the country's history the legislature had overruled the executive.
Some analysts said it was an indication of parliament's growing power.
But others argue that by getting rid of Mr Ringera, MPs have not solved the problem as the KACC still does not have powers to prosecute.