Gary Kirsten is to stand down as South Africa's coach for family reasons.
Kirsten was appointed on a two-year deal in August 2011, with an option of a further two years.
But having guided South Africa to the top of the Test world rankings - he never experienced defeat in six series - he has decided to step down in order to spend more time with his family.
Kirsten said: "I would like to thank Cricket South Africa for the confidence they showed in entrusting me with the fortunes of the national team.
"It has been a huge privilege to represent my country as player and coach and to have been given the responsibility of growing the team.
"I would particularly like to thank Cricket South Africa for allowing me the flexibility to combine my coaching job with my family life during my tenure.
"There have been many highlights over the past two years which have been well documented and I have every confidence that the Proteas will continue to go from strength to strength."
Cricket South Africa chief Chris Nenzani said: "Gary has a young family and it is understandable that he wishes to spend more time at home.
"I would like to thank him for his tremendous contribution to the wellbeing of the Proteas over the past two years.
"It is obvious to all of us, whether we have been close to the Proteas or simply fans watching from the stands, the standard of excellence that he has brought to our national team and it will be wonderful if he can complete his tenure by bringing home the ICC Champions Trophy next month.
"With the Proteas due to tour Sri Lanka in July and August and important home series coming up against India and Australia next season it is important that we move quickly to identify his successor.
"Gary certainly leaves the Proteas in good health and, although we are disappointed to lose him as head coach, he has put the foundations in place to carry us forward.
"We will certainly endeavour to retain his services in some capacity as his experience as player, coach and mentor is not something we want to lose in its entirety."
Before taking the South Africa job he was India's coach, and guided them to the 50-over World Cup title during a three-year tenure.