Tewari, a 1976-batch Indian Revenue Service officer, was posted as the Member (Legislation and Computerisation) in CBDT.
Sudha Sharma retired on February 28.Tewari has earlier served in various positions in the I-T Department, including as a Chief Commissioner in the national capital.
CBDT is a seven-member body, including the Chairman, and it is the apex authority for policy planning and administrative control over the I-T Department and collection of direct taxes in the country.