Kumaraswamy and Gandhi have discussed the future of the Congress-Janata Dal-Secular alliance in Karnataka.
JD-S Secretary General Danish Ali and Congress's KC Venugopal were also present in the meeting.
During the meet, Congress chief Rahul Gandhi has also confirmed his presence at the swearing-in ceremony of Kumaraswamy, scheduled to take place on Wednesday, May 23, 2018.
"I had a warm and cordial meeting this evening, in Delhi, with Shri H D Kumaraswamy ji. We discussed the political situation in Karnataka and other matters of mutual interest.
"I will be attending his swearing in as CM of Karnataka, on Wednesday, in Bengaluru," he said on Twitter.
I had a warm and cordial meeting this evening, in Delhi, with Shri H D Kumaraswamy ji. We discussed the political situation in Karnataka and other matters of mutual interest. I will be attending his swearing in as CM of Karnataka, on Wednesday, in Bengaluru. pic.twitter.com/sZAwX8mQut— Rahul Gandhi (@RahulGandhi) May 21, 2018
The oath-taking ceremony will also witness a gathering of non-Bharatiya Janata Party (BJP) chief ministers and chief of opposition parties such as Mamata Banerjee, Akhilesh Yadav, Narayanasamy, Chandrababu Naidu and K. Chandrashekar Rao.
Kumaraswamy has also invited Communist Party of India (Marxist) (CPI-M) general secretary Sitaram Yechury to attend his swearing-in ceremony.
On Saturday, Kumaraswamy was invited by Karnataka Governor Vajubhai Vala to form the government in Karnataka, after BJP leader Yeddyurappa resigned as the Karnataka chief minister ahead of the floor test at Vidhan Soudha.
While the oath taking ceremony was earlier scheduled to take place on Monday, the event later got postponed to May 23 due to the death anniversary of former Prime Minister Rajiv Gandhi on the day.
The Congress and the JD-S will hold a meeting on Tuesday in Bengaluru, where the modalities over power sharing would be worked out.
(With inputs from agencies)