United Airlines will remove Doha from its network later this year.
The Star Alliance member currently operates a daily Washington Dulles–Dubai–Doha service as a triangular route.
From August 30, this will become a direct Washington Dulles to Dubai service.
United will continue flying a B777-200ER in a two-class configuration, with 50 seats in business class and 226 in economy, to Dubai.
The move may be due to increased competition from Qatar Airways, which has been aggressive in its network expansion in recent years.
United last week launched its first-ever Chicago to Edinburgh service (see news, May 23).