David Marshall stepped down on grounds of ill health
Campaigning for the Glasgow East by-election will move up a gear on Friday.
Conservative candidate Davena Rankin will launch her campaign and Labour is expected to confirm who it wants to succeed David Marshall.
On Thursday, Glasgow councillor John Mason was chosen to represent the SNP. The Scottish Socialist Party (SSP) chose former MSP, Frances Curran.
Maths teacher Ian Robertson will represent the Lib Dems.
The vote will take place on 24 July.
Mr Marshall announced his resignation on health grounds.
Labour currently holds a 13,507 majority over the SNP.
The constituency also had the highest Labour vote share in the city at the General Election.
However, the party faces a tough fight after disastrous by-election results at Crewe and Nantwich and Henley, as well as the resignation of Wendy Alexander from the leadership of the Scottish Labour party.
Mr Marshall, 67, is stepping down after almost 30 years in the House of Commons.