Iowa State's Dan McCarney, the dean of Big 12 Conference coaches, resigned and North Texas fired coach Darrell Dickey on Wednesday.
McCarney, who has guided the Cyclones for 12 seasons, will remain with the team for the last two games.
"Sometimes you have to put the organization ahead of yourself. I think the best thing for this program right now is for me to step down," said McCarney, whose team is 3-7 this season, 0-6 in the Big 12 and has lost its last seven games against Division I-A opponents by an average of 20 points.
Dickey has had a series of health problems. In February, he had his gall bladder removed. In June, he was diagnosed with Type 2 diabetes. In October, he suffered a heart attack and missed the Mean Green's game at Arkansas State.
Dickey, in his ninth season, is 41-62.
Joe Paterno's doctor has ordered the Penn State coach to stay away from the field for Saturday's game against Temple.
Wayne Sebastianelli said that he would also prefer the 79-year-old Paterno, who is recovering from knee surgery and a broken left leg, stay off the field for next week's regular-season finale against Michigan State.
There's a chance Paterno will be allowed to coach from the press box.