The outgoing US President confirmed in a Sunday afternoon tweet that the previous New York mayor had caught the virus.
Mr Giuliani has travelled extensively to battleground states in current weeks in an effort to assist Mr Trump problem his election defeat.
Mr Trump wished him a speedy restoration.
“Get higher quickly Rudy, we are going to stick with it!!!” Mr Trump wrote in his tweet.
Mr Giuliani attended a listening to on the Georgia Capitol on Thursday the place he went with out a masks for a number of hours. A number of state senators additionally didn’t put on masks on the listening to.
On Wednesday night time, the lawyer was in Lansing, Michigan, to testify in a extremely uncommon four-hour legislative listening to wherein he pushed Republican lawmakers to disregard the certification of Joe Biden’s Michigan victory and appoint electors for Mr Trump.
He didn’t put on a masks, nor did lawyer Jenna Ellis, who was sitting subsequent to him. At one level, he requested one in every of his witnesses — a Detroit election employee — if she can be snug eradicating her masks however legislators mentioned they might hear her.
Earlier than the listening to, Mr Giuliani and Michigan Republican Celebration chairman Laura Cox — each maskless — did a digital briefing for Republican activists.
Mr Giuliani made an look earlier on Sunday on Fox Information to talk about his authorized challenges in a number of states on behalf of Mr Trump.
The analysis comes greater than a month after Mr Trump misplaced his re-election bid and greater than two months after Mr Trump was in poor health with the virus in early October.