Originally a private bus line started by Green Bus Lines in 1933, it is currently operated by the MTA Regional Bus Operations under the New York City Transit Authority brand.

The M50 begins at Pier 83 on the West Side, traveling north along 12th Avenue before running east along 50th Street to Second Avenue, where it transitions via Second Avenue to running on 48th Street to First Avenue before making two consecutive left turns onto 49th Street, where it terminates.

[2][3] In 1933, Green Bus Lines had initially received one-year franchises to operate six Manhattan crosstown bus routes, one of which was the M3.

[citation needed] On June 27, 2010, due to budget shortfalls within the MTA, the M27 was eliminated and M50 weekend service was discontinued.

[8] These changes were expected to save $1,900,000 annually, although weekend service on the M50 was brought back in exchange for truncating the eastern end of the route to 49th Street from United Nations on July 3, 2011.