Documents opposing the ruling were filed at Westminster Magistrates’ Court this morning.
The taxi-app firm had been set a deadline of 4.30pm today to formally appeal or go out of business in the capital.
TfL last month refused it a new licence on the grounds it was not a 'fit and proper' operator.
Around 3.5 million Londoners are said to use Uber. An estimated 40,000 drivers rely on the company for their livelihoods.
We have today filed our appeal so that Londoners can continue using our app. We hope to continue having constructive discussions with Transport for London.
– UBER SPOKESPERSON
Uber's new chief executive Dara Khosrowshahi met transport commissioner Mike Brown last week to discuss the firm's future in London.
The talks were described by both sides as "constructive".
Read more news of London here.