"Azhar Ali recently called on PCB Chairman Shaharyar Khan and informed him that he wished to relinquish the captaincy of Pakistan's ODI team mainly because it was affecting his batting form," the board said in a statement.
"PCB thanked him for his dignified leadership of the team and informed him that his standing in the team would not be affected by his relinquishing of the captaincy," it added.
Sarfraz, 29, took over as Pakistan's Twenty20 captain last year.
Under Azhar, Pakistan slipped to ninth in the one-day rankings before moving up a place to qualify for this year's Champions Trophy, a top-eight tournament, in England and Wales.
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(Reporting by Amlan Chakraborty in New Delhi; editing by Ed Osmond)
