The World Bank has granted Kenya $200m (£109m) in grants and loans, following the government's campaign to end corruption in the civil service.
The loan is a boost to Kibaki's government
Part of the money is earmarked for improving airport security and for agriculture projects, says Focus on Africa correspondent Muliro Telewa.
The World Bank's Makhtar Diop says the cash is linked to the anti-graft drive.
The Bank withdrew help for Kenya in the early 1990s blaming corruption and poor governance by ex-President Daniel Moi.
Kenyan President Mwai Kibaki had led initiatives to tackle the "roots of corruption," Mr Diop said at a ceremony on Friday.
Minister for Finance Daudi Mwiraria said the money would also be used to improve Nairobi's sewage and water system.
President Kibaki's National Alliance Rainbow Coalition (Narc) won the December 2002 elections on a promise to tackle widespread corruption.
The campaign has taken on many different forms.
This year, junior police officers had their pay doubled in an attempt to discourage them from taking bribes.
There have been numerous trials of officials alleged to have been engaged in corruption.