In a statement, Sean Bratches, managing director of commercial operations at Formula One, said that while "significant progress" in talks with various Miami authorities had taken place, the negotiations had been "complicated".
"Whilst our preference would have been to race in Miami in 2019, there was always a point by which delivering the best possible wheel-to-wheel racing experience for our fans, drivers and teams wouldn't be possible in the time available," Bratches said.
"We have now reached that point as far as racing in Miami in 2019 is concerned."
Nevertheless, he added: "However, we are taking a long-term view and as a result, we have decided, in consultation with the Miami authorities, to postpone sign-off until later in the summer, with the aim of running the first Formula 1 Miami Grand Prix in the 2020 season."
While it remains globally popular, F1 is still trying to make its presence felt in the US where the local IndyCar and NASCAR racing car series retain a large following.
This year's US Grand Prix takes place in Austin on October 21.