Two of the cases in the Zaatari camp were Jordanians who worked there and the third was a Syrian woman refugee, state-owned Mamlaka TV broadcaster quoted the governor of Mafraq area, Yasser al Adwan, as saying.
The United Nations refugee agency UNHCR said in a statement the infected refugee had been sent an isolation area and contacts were being traced. The camp hosts nearly 77,000 Syrians.
The UNHCR confirmed on Tuesday the first two cases of coronavirus among Syrians in the smaller Azraq camp since the pandemic was first reported in the kingdom.
There have been several other infections of Syrian refugees living outside the camps, among the 2,739 cases in Jordan since the first infection was reported on March 2.
Most of the more than 655,000 United Nations-registered Syrian refugees in Jordan live in urban centers.