Registration will now begin March 19. Organizers made the announcement Tuesday.
Organizers say the registration process was postponed to "finalize a routine yet comprehensive assessment of our new registration process."
Marathon organizers say the original deadline to register for the Bank of America-sponsored event remains the same - April 7. The race will be held starting in Grant Park on Sunday, October 12.
Last year, the online registration system crashed shortly after people began signing up. Race organizers eventually turned to a lottery to fill the remaining slots.
The Sun-Times Media Wire contributed to this report.