Show your valid Metro pass or Metro Rail ticket at the box office and get $1.25 off adult admission. There are two NHM-convenient stops on the Metro Expo Line: the Expo/Vermont station or Expo Park/USC station.
(Hints: The Expo/Vermont station brings you by our Dueling Dinos statue. The pretty, short walk from Expo Park/USC is adjacent to the Rose Garden and NHM's renovated 1913 Building.)