South African President Thabo Mbeki has mediated in talks to end a political crisis after Mugabe’s re-election unopposed in a June presidential poll that was boycotted by Tsvangirai and condemned around the world.
"President Mbeki is going to give a press statement but I can say that we have got a deal," Tsvangirai said as he left the venue of negotiations in the capital Harare.
A Zimbabwe government source also told Reuters: "They have reached some agreement, and President Mbeki, the mediator is going to announce that very soon."
Mugabe had earlier cast doubt that a deal was imminent, with his ruling ZANU-PF accusing the MDC of plotting with the West to strip him of executive powers in the talks.
But MDC spokesman Nelson Chamisa dismissed the charges of collusion with Western countries, which have imposed sanctions on Mugabe and his inner circle to try to force change.
Tsvangirai, who won the initial election in March but failed to secure an outright victory, stayed away from the June election run-off vote over attacks on his supporters.
Zimbabweans hope a deal can allow the revival of an economy in meltdown. Inflation is over 11 million percent and severe food and fuel shortages have driven millions across the country’s borders, straining regional economies.