Union Minister Arun Jaitley resumed charge as the Finance Minister on Friday, official sources said.
He returned from the US last week after undergoing medical treatment.
He attended a meeting of the Cabinet Committee on Security to discuss the Pulwama attack that killed 40 CRPF personnel, sources said.
In his absence, the charge of the Finance Ministry was given to Railways Minister Piyush Goyal, who presented the sixth and the last budget earlier this month before the general elections.
General elections are expected during April-May this year.
Jaitley left for New York on January 13 after being reportedly diagnosed with soft tissue cancer. Subsequently, on January 23, the charge of the Finance Ministry and Corporate Affairs was given to Goyal on a temporary basis.
This was his first overseas visit after he underwent renal transplant surgery on May 14, 2018, at AIIMS.
He had stopped attending office at the beginning of April last year due to his kidney ailment and was back in North Block - the seat of Finance Ministry - on August 23, 2018. Even then, Goyal had manned the ministry for about 100 days.
Jaitley in September 2014 underwent bariatric surgery to treat weight gain that he suffered because of a long-standing diabetic condition.