The 34.3 million viewers who tuned in to the Academy Awards represented that annual ceremony's smallest audience since 2008.
The Nielsen company said Monday that Oscar viewership was down from the 37.3 million who watched the ABC show in 2015.
In 2014 and 2013, the show reached more than 40 million viewers each year.
The ceremony, hosted by Chris Rock, came amid controversy about a lack of diversity among the nominees and calls for a boycott among some minority fans. There was no immediate way to judge whether the controversy affected ratings, or whether other factors held the audience down.
The lowest rating came in 2008, when Jon Stewart served as host and the telecast attracted approximately 32 million viewers.
Many years, the Oscars are television's biggest event after the Super Bowl.