Following a spate of passengers alleging to have been raped, kidnapped or groped by their Uber drivers, the ride-hailing company is introducing the 911 button to make passengers in the US feel safer.
Sachin Kansal, Uber's head of safety products, told CNet.com: "Users have told us, 'Something to give me peace of mind is a way to access emergency features.'
"We are making this very accessible right from the home screen."
There have also been reports of some Uber drivers being attacked by passengers and the company revealed plans to add the feature to its driver app later this summer.
The button will allow users to call the emergency services simply by hitting the button.
Uber is also pilot testing a new feature in seven cities that will send the passengers' location and trip details to the police automatically as soon as they hit the button.
Kansal said: "In such situations, every second counts."
Nine women in the US are currently suing the company, claiming to have been sexually assaulted by drivers.
This is the latest in a strong of safety features Uber has introduced in repose.
Last month, it announced it was toughening up driver screenings, requiring annual background checks, as well as trialling a new in-app design that will stop giving drivers a log of passengers' pick-up and drop-off addresses.