The man fell to the ground floor during Thursday night's clash against the Minnesota Vikings, and frantic witnesses called police over to where his body had landed, Police Department spokesman John Cannon said. He later died at a Houston hospital.
Authorities cannot identify the man until his family has been informed, Cannon said, adding that police are investigating what appears to have been an accidental fall.
Mark Miller, the general manager of SMG-Reliant Park where the stadium is located, said the man was travelling down from the fifth floor when he fell about 18 metres to the ground. Two medical teams working at the stadium treated the man at the scene before he was transported to Memorial Hermann Hospital where he died, he said.
Staffers monitor fan safety at each escalator landing, Miller said.
"We make sure they're not overloaded and we try to operate them in the safest possible manner," Miller said.
The bank of elevators in the northeast corner of the stadium where the fall occurred has been closed for inspections and Reliant Park officials are reassessing safety procedures, he said.
Texans' president Jamey Rootes said the stadium complies with safety rules.
"We have our procedures in place, the league has a whole comprehensive set of best practices relative to fan behaviour and stadium security," Rootes said. "We've always been rated at the very highest level ... I don't know that anything changes" in view of the fatal fall.
The Texans open the regular season Sept. 9 with a home game against the Miami Dolphins.
In 2011, a firefighter attending a Texas Rangers game in Arlington died when he fell from the left field stands while reaching for a baseball tossed his way by all-star outfielder Josh Hamilton.
Shannon Stone fell about six metres onto concrete when he tumbled over the left-field railing after catching the ball and falling into an area out of sight from the field as the Rangers faced Oakland. Cooper Stone, his nine-year-old son, witnessed the fall during the second inning.
In April, a statue of Stone and his son was dedicated to Rangers fans in front of the home plate gate at Rangers Ballpark in Arlington. Railings also were raised throughout the ballpark before this season.
Associated Press writer Diana Heidgerd contributed to this report from Dallas.