pitched for "a collective effort" by party leaders to "overcome" the challenges it faced from Prime Minister Narendra Modi and BJP chief Amit Shah.
Ramesh also said that business as usual approach will not work against Modi and Shah and advocated for a flexibility in approach to make Congress relevant.
"Yes, the Congress party is facing a very serious crisis," Ramesh said on Monday.
He said the Congress had faced "electoral crisis" from 1996 to 2004 when it was out of power. The party had also faced "electoral crisis" in 1977 when it lost the elections held soon after the emergency.
"But today, I would say that the Congress is facing an existential crisis. It is not an electoral crisis. The party really is in deep crisis," he said, when asked whether the threat of "poaching" of MLAs posed by the BJP in Gujarat had forced the party to transport its MLAs to Karnataka to ensure party leader Ahmed Patel's victory in the Rajya Sabha polls.
He, however, justified the Gujarat Congress's decision to send 44 of its MLAs to a resort in party-ruled Karnataka on July 29 to fend off the alleged "poaching" attempts by BJP, saying the saffron party had also "transported" MLAs in the past.
He said it was wrong for the Congress party to think that anti-incumbency will work automatically against the Modi-led government in the states being ruled by the BJP in the elections.
"We have to understand we are up against Mr Modi, Mr Shah. And they think differently, they act differently, and if we are not flexible in our approach, we will become irrelevant, frankly," the Congress leader said.
He said the Congress party must also recognise that India has changed. "Old slogans don't work, old formulas don't work, old mantras don't work. India has changed, the Congress party has to change," he said.
The former union minister hoped that party vice-president Rahul Gandhi would end the uncertainty over his taking over as the Congress president to make the party ready for crucial electoral battles in key states in 2018 and the Lok Sabha polls scheduled a year later.
"I think in all probability, Rahul Gandhi will take charge (as Congress president) before the end of 2017," he said.