Pittsburgh Public Safety Director Michael Huss told reporters Sunday that the 23-year-old man collapsed near paramedics at the 12-mile mark near Duquesne University.
Officials said the victim was taken to UPMC Marcy Hospital, where he was pronounced dead.
His name was not released. An autopsy by the Allegheny County coroner's office was scheduled Monday.
Race director Patrice Matamoros said on the marathon's website that "This is a loss for the entire marathon family and our hearts and prayers go out to his family at this time."
