Asfari is retiring to focus on his family, health and charitable interests.
Iskander joins in November as deputy chief executive before taking over from Asfari on January 1 2021. Asfari will meanwhile remain with the company as a non-executive director in order to support the transition.
"After nearly 40 years in the industry and 30 years with Petrofac, Ayman has decided the time has come to step back from his executive duties to focus on his family, health and charitable interests,” said René Médori, Petrofac chairman.
“The board has been planning for his retirement for some time and I am delighted that we have been able to attract a candidate of Sami Iskander's calibre, who was identified following a comprehensive external and internal search process.
“He has an excellent industry pedigree both in international oilfield services and upstream E&P, a deep and local understanding of our markets and client landscape, and a proven track record in business transformation.”
In the statement, Asfari commented: “There is never a perfect moment to step down, and it has been a difficult decision for me to make. However, I have decided now is the time to hand over the day-to-day running of the Company to fresh leadership.”
“As a major shareholder I remain deeply invested in Petrofac's future and I am confident of the group's continued progress and success in the coming years."
Iskander, meanwhile, added: "I am delighted to be joining Petrofac at a pivotal and exciting time for the business.
“Petrofac is a truly outstanding company, with a best-in-class execution track record, a strong and differentiated competitive position in attractive core markets, and a growing new energies business. I have the utmost respect for what Ayman and Petrofac's team have built. I look forward to working with them over the coming years to lead this fantastic company to deliver growth and create value for all of its stakeholders."