Gandhi has been appointed Deputy Governor for a period of three years effective today, RBI said in a statement.
He was Executive Director of the Reserve Bank before being elevated to the post of Deputy Governor.
Gandhi will look after portfolios such as Banking Operations and Development, Non-Banking Supervision, Urban Banks Department, Expenditure and Budgetary Control, Information Technology and Legal Department.
Having joined the RBI in 1980, Gandhi has built over 33 years expertise and experience in varied fields which include, payment systems and information technology, financial markets, operations and regulation.
He had a three-year secondment to the Securities and Exchange Board of India.
Sinha, who was looking after the new bank licence process had retired in January.
The Reserve Bank has four Deputy Governors -- two from within the organisation, one economist and one banker.
Another vacancy for a Deputy Governor will arise as K C Chakrabarty has requested to be relieved on April 25, slightly earlier than his scheduled term end on June 30.
H R Khan and Urjit Patel are the other Deputy Governors of RBI.