The Liberal Democrat candidate for the South Staffordshire constituency has died following a short illness, it has been confirmed.
Jo Harrison, 53, died at her home in Kinver on Saturday morning.
A spokesman for the Lib Dems said her death had not been sudden but would not reveal the nature of the illness.
As a result of her death, the constituency election on Thursday will be abandoned and called for next month instead.
In a short statement the party's chief executive, Chris Rennard, added: "Jo has been ill for some weeks and will be sadly missed.
"Our sympathies go out to her family."
A spokesman for the Department of Constitutional Affairs said that if a candidate died after the nominations period had closed then any voting, such as postal votes, must be abandoned and restarted.
A new poll will be called 28 days after the returning officer is given proof of death, he added.
Ms Harrison polled in third when she contested the seat in the 2001 General Election, winning 4,891 votes.
The MP elected then, Conservative Sir Patrick Cormack, gained a majority of 6,881 votes over the second place Labour candidate.
Sir Patrick paid tribute to Ms Harrison saying: "I am obviously extremely distressed at the death of my Liberal Democrat opponent, and very sorry indeed that I am not going to be in a position to return to Westminster on 11 May, but we will be doing everything possible to ensure we come back at the by-election."
Standing Labour candidate, Penny Barber, added: "It is a huge shock and a terrible shame.
"Our thoughts go out to her family and friends."