Scotland's top cup competition for Under 19 players traditionally gives the talented youngsters the opportunity to play on the main club stadium, and with St Johnstone, Celtic and Dundee United having no first team fixture this weekend it means the full focus will be on their efforts in the Youth Cup.
On Saturday, St Johnstone face Celtic at McDiarmid Park, kick-off 1 pm, with the winners at home to St Mirren in the quarter final.
The following day Dundee United meet Rangers at Tannadice, also with a 1 pm start.
Full fixture details for the two remaining fourth round ties and the known dates of the quarter finals are:
Saturday, 4 February
St Johnstone v Celtic, 1 pm
Sunday, 5 February
Dundee United v Rangers, 1 pm
Fifth Round
Sunday, 19 February, 2006
Aberdeen v Ross County, Pittodrie Stadium, 2 pm
To be arranged:
Inverness Caledonian Thistle v Livingston
Dundee United or Rangers v Heart of Midlothian
St Johnstone or Celtic v St Mirren