The episode titled "10 Years Later: The Truth about Columbine" was to air Monday, the anniversary of the massacre in Littleton, Colo., that killed 12 students and a teacher.
Winfrey posted a message Monday morning on her Facebook page, saying that after she reviewed the taped show she decided to pull it because of its focus on the two gunmen.
She urged viewers to keep the Columbine community in their thoughts.
Winfrey said she would air a program about a mother released from prison in place of the Columbine piece. Her company Harpo Productions confirmed the announcement.