Prime Minister Modi took to twitter and wished for her long life and good health.
Gandhi took over as the party president in the year 1998.
Meanwhile, Congress party workers and leaders gathered in numbers to celebrate the special day of their leader outside 10 Janpath in Delhi.
"Compassionate, hardworking, selfless. Calm and composed, yet dignified and strong. A force for empowerment against all odds. A mother, a leader, a friend. Wishing Congress President Sonia Gandhi a very happy birthday", read the tweet. (ANI)