Swaraj, one of India's best-known female politicians and a veteran leader of the ruling Bharatiya Janata Party (BJP), tweeted that she was undergoing dialysis at a private hospital in New Delhi.
"I am in All India Institute of Medical Sciences (AIIMS) because of kidney failure . Presently, I am on dialysis," the 64-year-old tweeted from her verified account, which has over 6.5 million followers.
"I am undergoing tests for kidney transplant . Lord Krishna will bless."
The Press Trust of India news agency said Swaraj, who suffers from chronic diabetes, had been admitted to AIIMS on November 7.
Millions of Indians suffer from kidney disease, mostly because of high rates of diabetes.
But the country has low rates of organ donation and a chronic shortage of organs available for transplant has fuelled a black market.