OKLAHOMA CITY (AP) Donnie Duncan, a former Oklahoma athletic director and Iowa State football coach, has died at the age of 75.

Son-in-law Patrick Reardon says Duncan, who suffered from cancer, died in his sleep Saturday in Dallas.

Duncan was on Barry Switzer's Oklahoma football staff from 1973-78, and he helped the Sooners go 62-6-2.

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He went 18-24-2 in four seasons at Iowa State. His 1980 and 1981 Cyclone squads were ranked, and the 1981 Cyclones began 5-1-1 and were ranked as high as No. 11 in The Associated Press poll. Duncan's squads went 3-1 against Iowa, including three straight wins in 1980, 1981 and 1982.

Duncan was executive director of the Sun Bowl and Gator Bowl before returning to Oklahoma. He was athletic director from 1986-96. He became Big 12 director of football operations when the conference formed in 1996.