352,000 more listeners tuned into commercial radio each week than listened to BBC stations in the first quarter of 2017.
Commercial radio attracted 34.53 million weekly listeners in the three months to 2 April 2017, growing 0.7% year on year, compared to 34.18 million who listened to BBC stations.
Overall the numbers listening to the Beeb shrank by around 2% year on year, giving commercial radio the advantage.
The last time that commercial radio was ahead of the BBC was in Q2 last year, when it pulled ahead by some 500,000 listeners.
Michael Williamson, head of AV planning at Carat, said: "The latest Rajar results show that commercial radio is in rude health, as it closes the gap on the BBC for total listening figures.
"Commercial radio also has a higher digital share than the BBC extending its superiority against the BBC for adults aged 15-44 listening. It’s a good time for agencies and advertisers to take advantage of audio as a way of reaching consumers."
Although the major commercial radio stations did not have an especially buoyant start to the year, the most popular BBC offerings also took a hit.
The behemoth of Radio 2 dipped 0.2% over the quarter to just over 15 million listeners, a year-on-year slide of 3.2%, while Radio 4’s audience was down 1.9% to 11.11 million listeners compared to Q4.
Meanwhile, Radio 1 was down to 9.1 million listeners, which represented an 8.1% downturn on the same time last year and 4.8% on Q4.
In contrast, there has been some year-on-year growth in national commercial radio, notably Capital network (2.8%), Classic FM (4.7%), and LBC network (15.5%).
Williamson pointed out that talk radio benefited from the "unsettled political and economic environments".
"We expect the Q2 Rajar results to show a continued trend with the UK election, Brexit and cyber hacking all front of mind," he added.
Meanwhile, Havas Media publishing manager Rich Hall said: "No one is under any illusion that LBC will do very well with the political uncertainty. It is really good for commercial radio as it’s great for both advertisers and the public to have a strong talk radio show."
The latest Rajar figures show that 48.2 million adults tuned into the radio each week in the first quarter of 2017, up by around 400,000 listeners on the same quarter last year.
Digital listening is up, with 59% of the population tuning in each week, and Bauer Media’s group commercial director Simon Kilby said the medium was a "great success".
"When people get more exposed to good digital radio, they end up consuming more radio overall," he added.