The Croatian announced the news on Instagram, revealing it took a third test to confirm he had been infected.
Ivanisevic, 48, was a director of the Adria Tour, the recent ill-fated set of tournaments that Djokovic put on in an effort to raise money for charity.
Four Adria Tour players, including world No.1 Djokovic and Grigor Dimitrov, have tested positive for COVID-19.
Ivanisevic wrote: "Unfortunately, after two negative tests in the past 10 days, I have just found out that I tested positive for COVID-19.
"I feel good and don't have any symptoms. I would like to inform everyone who has been in contact with me that I tested positive and ask them to take extra good care of themselves and their loved ones.
"I will continue to self-isolate as I have been doing already. I wish everyone who got infected a speedy recovery."
Ivanisevic, who was famously a wild-card entrant when he landed the 2001 Wimbledon title, was closely involved in the Zadar leg of the tour last weekend, mixing with Djokovic and a host of leading men's tennis stars as they visited Croatia.