The North East Lanarkshire by-election was a Parliamentary by-election. It returned one Member of Parliament to the House of Commons of the United Kingdom, elected by the first past the post voting system.
Sir William Henry Rattigan had been Liberal Unionist MP for the seat of North East Lanarkshire since the North East Lanarkshire by-election, 1901. He died on 4 July 1904 at the age of 62.
The seat had been Liberal Unionist since they gained it in 1901;
Polling Day was fixed for 10 August 1904.
The Liberals gained the seat from the Conservatives;
At the following General Election the result was;