A total of 19,867 new companies were registered in the borough during 2015, putting it ahead of Hackney (18,531) and Camden (17,955) as the most popular place for new firms to be formed.
That's according to figures compiled by the company records management website Inform Direct using data from Companies House and the Office of National Statistics.
Kensington & Chelsea , where 3,783 new companies were formed during 2015, props up the table for west London start-ups.
Last year saw a record number of new businesses created across the capital, with 198,282 new registrations compared with 191,915 in 2014. A total of 119,720 businesses in the capital were dissolved during 2015.
Henry Catchpole, managing director of Inform Direct, said: "Of course London has always stormed ahead in business but this is its most successful year to date in terms of start-ups.
"For the first time ever there are one million companies registered in the capital with boroughs like Hackney, Camden and Westminster leading the way for the entrepreneurs."
Across the UK, there were 612,565 firms formed last year - up from 586,784 in 2014 - according to the Inform Direct Review of UK Company Formations in 2015, which was published this week.
The report can be viewed in full here .
|Borough||New companies formed in 2015|
|Hammersmith & Fulham||3,845|
|Kensington & Chelsea||3,783|
* figures according to Inform Direct