It said in a statement the requirement remained in force under anti-money laundering rules.
"The Reserve Bank clarifies that, in applicable cases, linkage of Aadhaar number to bank account is mandatory under the Prevention of Money-laundering (Maintenance of Records) Second Amendment Rules, 2017," it said in a statement.
The RBI also said that anti-money laundering rules announced in June 2017 have "statutory force" and banks have to implement them without awaiting further instructions.
The Aadhaar programme, which is the world's largest biometric identity card programme, has triggered some claims that it is an infringement of privacy of citizens.
The Supreme Court in August had said that privacy is a fundamental right and the verdict was expected to complicate efforts of Prime Minister Narendra Modi's government to make linking of the ID card numbers with bank accounts, telephone numbers, etc.
Source: NDTV Profit