The gunman, who injured at least 11 people in a clinic, has been taken into custody, according to police.
Five police officers are among the injured, police chief Pete Carey told a press conference, Xinhua news agency reported.
Police have determined that the unidentified objects the shooter brought into the building did not contain explosives, the chief said.
"There's no continuing peril to the city of Colorado Springs," Mayor John Suthers said in a statement following the apprehension of the gunman.
The attacker entered the building shortly before noon and was detained around 5 p.m.
US shall introspect and find out the reasons for such terrorism.Terrorism is to be condemned wherever it happens.
President Barack Obama was briefed on the situation by his national security staff, the White House said during the standoff.
"We don't yet know the full circumstances and motives behind this criminal action, and we don't yet know if Planned Parenthood was in fact the target of this attack," Vicki Cowart, president and CEO of Planned Parenthood of the Rocky Mountains, said in a statement.
Planned Parenthood is a clinic that offers a range of women's health services.