Razak visited the Jama Masjid mosque near Parliament at around 1 pm and stayed there for half an hour, a senior police official said.
A heavy security cover was thrown around the area in view of Razak's visit to the mosque.
Razak was among 10 ASEAN leaders who witnessed the Republic Day parade at the majestic Rajpath which showcased the country's military might and cultural diversity.
Signifying India's fast growing strategic ties with ASEAN, leaders of all the 10 countries of the powerful bloc were invited as chief guests for the parade.