Finnish defender Aapo Halme was the first arrival, joining from HJK Helsinki in a £500,000 deal.
Japan international midfielder Yosuke Ideguchi was next through the door at Elland Road before immediately heading to partner club Cultural Leonesa on loan until the end of the season.
Belgian left-back Laurens De Bock was captured for £1.5million from Club Brugge on January 11 before Benfica loanee Oliver Sarkic sealed a permanent switch hours later.
Leeds then spent their biggest fee in more than 10 years to capture midfielder Adam Forshaw from Middlesbrough.
The latest arrival was 17-year-old striker Sam Dalby from Leyton Orient.
In terms of departures, Cameron Borthwick-Jackson was sent back to Manchester United while Liam Kitching and Malik Wilks joined Harrogate and Grimsby on loan respectively.
Express Sport brings you the possible ins and outs at Leeds before the January transfer window slams shut.
Andy Lonergan – OUT – To Sunderland
Sunderland have enquired about signing the 34-year-old goalkeeper.
According to reports, Lonergan has agreed an 18-month contract with Sunderland.
Leeds are happy for him to leave but will only green light his departure once a replacement has been sought.
Adam Bogdan – IN – From Liverpool
The Liverpool goalkeeper is being considered as a potential replacement for Sunderland target Lonergan.
He recently returned to full training after a lengthy spell on the sidelines with a knee injury.
Bogdan is well down the pecking order at Anfield but finances will dictate any potential move for his signature.
Pascal Struijk – IN – From Ajax
A deal for the 18-year-old centre-back is likely to be concluded today.
Struijk – out of contract at the end of the season – has travelled to England to seal a move to Elland Road.
He has never made a first-team appearance for Ajax and will initially link up with Leeds’ Under-23 team.
Giovanni Troupee – IN – From FC Utrecht
The season-ending injury suffered by Luke Ayling threw a spanner in the works for Leeds.
It was thought that Laurens De Bock’s arrival would free Gaetano Berardi to shuffle across to right-back but reports in Holland suggest a loan deal for FC Utrecht defender Troupee could happen.
A trio of Italian club are also interested.
Tyler Roberts – IN – From West Brom
Leeds are on the hunt for a striker and fancy Roberts, who is out of contract at the end of the season.
An offer worth in the region of £4m was snubbed by West Brom but the Baggies could be tempted to cash in to avoid losing him for minimal compensation in the summer.
However, Thomas Christiansen indicated he doesn’t need a new forward after Pierre-Michel Lasogga bagged a brace in the defeat against Millwall.