The Blues beat Norwich City on penalties in their third round replay last week, meaning United will travel to Stamford Bridge on Sunday, 28th January (kick-off 1.30pm UK time).
Tickets went on sale to all season ticket holders last week and were released to members on Monday. General sale began at 10am on Tuesday.
Newcastle have been allocated 3,000 tickets, with a few hundred still remaining, and prices are £30 for adults and £15 for juniors (under-20s) and seniors (65 and over).
Please note that the deadline for posting tickets out is 3pm on Wednesday, 24th January.
Members get priority on tickets and benefits including an exclusive membership pack, discount on food and drink at NINE Bar and money off stadium tours.
Find out more about becoming a member here.
To secure your seat, please visit tickets.nufc.co.uk, call 0844 372 1892 (calls cost 7p per minute plus your network access charge) or, when applicable, visit the St. James' Park box office in person.