جامعة الملك فهد للبترول والمعادن
In 1981, he became visiting professor of physics and mathematics at the University of Iowa and Virginia Polytechnic Institute and State University, now Virginia Tech. In 1982, Riazuddin came back to Pakistan where he joined Quaid-e-Azam University as a professor of theoretical physics. In 1982, Riazuddin also went to Saudi Arabia where he joined King Fahd University of Petroleum and Minerals and became Chairman of the Department of Mathematics and Statistics and also taught physics at the Department of Physics. In 1983, Riazuddin, along with Asghar Qadir, went to Trieste, Italy, to join the International Centre for Theoretical Physics. Both scientists joined Salam where they continued research in their fields. In 1998, Riazuddin left King Fahd University of Petroleum and Minerals and returned to Pakistan to rejoin PAEC.