India-born Labour MP Ashok Kumar, who was known as a natural fighter and community leader in his north-east England constituency of Middlesbrough South and East Cleveland, was on Monday found dead in his house.
Kumar, 53, suffered a "sudden accidental" death, his office has said.
"At this stage it is too early to say whether the death is being treated as suspicious and inquiries are ongoing," a police spokesman said.
House of Commons speaker John Bercow paid tributes to Kumar at the start of business.
"It came as a huge shock to everyone. Ashok was a fine politician who served his constituency and his constituents with diligence and unswerving commitment," a spokesman for Kumar's office said.
"He was a natural fighter and a community leader. He first won his seat in 1991 in a by-election, only to narrowly lose it in the 1992 general election. Undaunted, he stood again and in 1997 regained the seat and successful defended it in following contests," he added.
Announcing the news to the House of Commons on Monday afternoon, Bercow said, "Ashok was a most assiduous Member, much respected by the House and by professional background a very fine chemical engineer.