Djokovic, who said his wife Jelena had also contracted the illness, joins Grigor Dimitrov, Borna Coric and Viktor Troicki who had all featured in the first two legs of the Adria Tour in Serbia and Croatia.
“Novak is not showing any symptoms,” said a statement from Djokovic’s spokesman.
Djokovic, 33, hosted the first leg of his brainchild at his tennis centre in his home town of Belgrade.
"I am extremely sorry for each individual case of infection," said Djokovic, who added that his two children had not tested positive.
"I hope that it will not complicate anyone's health situation and that everyone will be fine.”
Djokovic added: "Everything we did in the past month, we did with a pure heart and sincere intentions. Our tournament meant to unite and share a message of solidarity and compassion throughout the region."
Dimitrov, the world number 19, announced on Sunday he had tested positive after pulling out of the event in the Croatian resort town of Zadar. Coric and Troicki revealed their illnesses on Monday.
Tour over
Following Tuesday’s announcement, the Bosnia leg of the Adria Tour was cancelled.
"Unfortunately, due to all events in the past days we decided that now the most important thing is that the epidemiological situation is stabilised and everyone recovers," said tournament director Djordje Djokovic.
"Now we remain focused on the support to all those infected ... wishing that they recover as soon a possible.”
Around 4,000 fans watched the first leg of the tournament in Belgrade in early June while a similar crowd attended the Zadar event.
The four-nation tour should have culminated in Sarajevo on 5 July after sessions in Banja Luka.
"What was meant to be a major, nice tennis story ended with an even bigger collapse," Croatia's Sportske Novosti daily newspaper said on Tuesday. "Damages could be immense, for both the health of many and Croatia's tourism.”
