The British champion was due to put his WBA, IBF, WBO and IBO belts up for grabs against Bulgarian challenger Pulev at the Tottenham Hotspur Stadium in London on June 20.
But the global spread of COVID-19 has put paid to the bout on that date.
“Anthony Joshua’s defence of his IBF, WBA, WBO and IBO heavyweight world titles against mandatory challenger Kubrat Pulev scheduled to take place at the Tottenham Hotspur Stadium on Saturday June 20 has been postponed,” said a Matchroom statement.
“A new date for the event promoted by Matchroom Boxing and 258 Management in association with Top Rank and Epic Sports Entertainment is currently being worked on.
“We will announce any updates in due course and continue to explore the possibility of hosting this fight at the Tottenham Hotspur Stadium.”
This is the second time Pulev has missed out on the chance to face Joshua after a shoulder injury forced him out of a world title bout in October 2017.
Earlier on Friday, Eddie Hearn, Joshua’s promoter, said his champion’s lone contest of 2020 might be with Tyson Fury in a world unification bout if the spread of COVID-19 means he only has time for one bout this year.
A clash with compatriot Fury, the WBC heavyweight champion, would be one of the most eagerly anticipated contests in British boxing history.