Nearly 210 million of old 1,000 shilling ($10) notes has been returned, the central bank announced.
In June Kenya introduced new banknotes, to curb corruption and money laundering, and citizens were given till Monday to return the old notes.
The design of the new currency, features an image of a statue of Kenya's first President, Jomo Kenyatta - the current President’s father, BBC reported.
“This means 7.1 billion shillings became worthless pieces of paper,” bank governor Patrick Njoroge told journalists.
A total of 3,172 suspicious transactions were flagged during the demonetisation and will be investigated.
Kenyan returned 210million of old shilling but central bank says 7.1 billion shillings is worthless paper. Video: Zodidi Dano/African News Agency
According to BBC Africa Tax Justice Network said the country has been losing $400million a year since 2011 through illicit financial flows.