Detectives on Tuesday arrested one suspect caught with Sh1.5 billon in fake dollars in a room at Eden House Flats in Pangani Shopping Centre.
Yassin Ahmed Osman was caught with more than $15 million (Sh1.5 billion), which were confirmed to be fake.
Detectives said the fake currency was packed in a black bag.
The suspect has been placed in police custody as detectives based in Starehe continue with the operation to apprehend more perpetrators.
In October, police arrested three suspects in Ruiru with Sh102.2 million in fake currency.
Kiambu county commissioner Wilson Wanyanga said DCI detectives raided a home within the town after a tip-off from members of the public.
Wanyanga said a chemical used to clean the money was also recovered.
He urged Kenyans to be aware of fake notes in circulation.