Arun Jaitley had stopped attending office in April for a renal transplant operation on May 14.
Union minister Arun Jaitley arrived in parliament on Thursday for his first appearance in the monsoon session.
Mr Jaitley, the leader of the Rajya Sabha, participated in the vote for the post of Deputy Chairman of the house. Every vote counts in a contest that has gone down to the wire, with the government and the opposition both fielding candidates.
The minister returns after a three-month hiatus. All the members cutting across party lines greeted Mr Jaitley by thumping their desks. He then cast his vote in the election for Deputy Chairman.
Rajya Sabha Chairman M Venkaiah Naidu requested the lawmakers to not go too close to Mr Jaitley or touch him, presumably as per the medical advice. Prime Minister Narendra Modi, who arrived in the house later, tried to shake hands with him, but the latter just greeted him with folded hands.
Mr Jaitley, 65, stopped attending office in April for a renal transplant operation on May 14.
On that day, the charge of his finance ministry was handed to Railways Minister Piyush Goyal.
Mr Jaitley had a bariatric surgery soon after the BJP-led coalition came to power in 2014. The surgery was to treat weight gain that he suffered because of a long-standing diabetic condition, according to the Press Trust of India.
A Rajya Sabha member since 2000, Mr Jaitley was re-elected to the house from Uttar Pradesh in March.
Mr Jaitley has been active on social media for the last few weeks, from taking on opposition parties to writing on issues including cuts to the goods and services tax rates.
Yesterday, in a Facebook post, he hit out at his former colleagues Yashwant Sinha and Arun Shourie for raising allegations in connection with the Rafale fighter deal. He called the allegations "unsubstantiated" and "reprocessed lies" and said these are being levelled by forces which are increasingly desperate to prove their relevance.
"There is not a grain of truth in the wild allegations repeated today nor anything substantiating in the purported facts and voluminous documents marshalled to corroborate the baseless accusations," Mr Jaitley said in his post titled 'The Rafale Falsehood Repeated'.
He is expected to start work in the Finance Ministry from August 16.
(With inputs from IANS)