At the Indian High Commission in the Pakistani capital, High Commissioner Sharat Sabharwal hoisted the national tricolour at an official function.
Sabharwal read out President Pratibha Patil's address to the nation on the eve of Republic Day and children of the High Commission's staff performed patriotic songs.
The function was held at the High Commission within the high-security diplomatic enclave in the heart of Islamabad.
Besides the traditional function held in Islamabad, the Indian High Commission will host two events in Lahore on January 27 and Karachi on January 29 to mark the Republic Day.
Leading businessmen, politicians, civil society activists and journalists have been invited to these events, at which the High Commissioner will be present.
Last year, the Indian High Commission hosted an event to mark Republic Day in the financial hub of Karachi for the first time in over 15 years.
The last such event was held before the consulate in the city was shut down in late 1994.
Indian High Commissioner in Singapore, T C A Raghavan led the Indian community in the city state to celebrate the day.
He unveiled the national flag and read out the President's message to some 500 Indians gathered at the High Commission.
Students from Indian schools in Singapore sang patriotic songs and danced at the celebration held this morning.
Indians in the Saudi Arabian capital Riyadh marked a more sombre celebration, using the day to organise a blood donation camp.