Waqar Younis will quit as Pakistan coach for medical reasons after next month's tour of Zimbabwe, he said on Saturday.
Waqar, whose contract was due to run until 2012, announced his resignation at a news conference in Lahore.
"I have no issues with anyone but because of medical reasons I have decided I can't continue as coach after the Zimbabwe tour," said the former fast bowling great without elaborating.
"The PCB (Pakistan Cricket Board) has accepted my resignation," he added.
Waqar, 39, lives in Sydney and the board's chief operating officer Subhan Ahmad told Reuters that he needed to go to Australia for treatment.
"We didn't want him to go but after he explained things to us we understood he needed to be with his family," Ahmad said.
"We are thankful to him that he agreed to go to Zimbabwe. We will now begin the process of looking at suitable candidates for the coaching position," he added.
Former Test captain Waqar was appointed coach after the team suffered a poor tour of Australia last year.
His resignation comes at a time when the PCB has just made wholesale changes to the backroom staff, removing long-serving manager Intikhab Alam and assistant coaches Aaqib Javed and Shahid Aslam.
The board said the trio needed to give more time to their duties at the national cricket academy.
Governing board member Naveed Akram Cheema will be the manager in Zimbabwe and former Test batsman Ijaz Ahmed the assistant coach.
Waqar took charge after Pakistan were whitewashed in Australia on a tour where he worked as bowling consultant.
He had a tough time during the 2010 series in England after then-captain Salman Butt and pacemen Mohammad Asif and Mohammad Amir became involved in a spot-fixing scandal.
Pakistan then enjoyed a good 50-over World Cup under Waqar's supervision earlier this year, reaching the semi-finals.
After the tour to West Indies this May, former one-day captain Shahid Afridi spoke of differences he had with Waqar over selection issues.
Waqar, who took 373 wickets in 87 Tests and claimed 416 victims in 262 one-day internationals, underlined that his decision to resign had nothing to do with the recent changes in the Pakistan set-up.
"I am now living in Sydney with my family and I need to spend more time there," he said.
"I have enjoyed the challenges of working with the Pakistan team. I am disappointed I won't be able to continue with them in this transition period."
The tour of Zimbabwe includes one Test, three one-dayers and a Twenty20 international.