The decision was taken during a meeting between opposition parties presided over by co-chairperson PPP Asif Ali Zardari.
Talking to media after the meeting, ANP leader Asfadyar Wali said all the opposition parties had agreed to nominate Mr. Rabbani as Senate chairman.
He added that the slot of deputy chairman will be given to a candidate from Balochistan.
Speaking on the occasion, Raza Rabbani thanked Asif Zardari, Asfandyar Wali, Chaudhary Shujaat, and other leaders for imposing confidence in him as nominee for Senate chairman.
MQM leader Dr. Farooq Sattar said unity needs to be maintained in future as well. He said Senate elections hold immense importance. He said all provinces must have equal representation in Senate.