The `Toxic` hitmaker - who has been under a legal conservatorship following her 2008 breakdown which gives her dad Jamie control over all her affairs - has had a number of conditions placed upon her in order to stop her from getting out of control.
It is thought owning her own phone could land the 29-year-old singer in trouble, so those close to her have removed it to keep her "under control".
An insider told The Sun newspaper: "Britney`s inner-circle keep a close eye on her to ensure she keeps herself together.
"One of the rules is she gave up her cell phone. That helps them keep her under control."
The move comes after the star - who has sons Sean Preston, five and Jayden James, four, with ex-husband Kevin Federline - was accused by her former bodyguard Fernando Flores of sending him nude pictures of herself from her phone, and then threatened to use them in a lawsuit against her.
In March, the pop superstar admitted she didn`t have access to a mobile device.
Speaking in a feature entitled `25 Things You Don`t Know About Me`, Britney said: "I don`t own a cell phone."
Meanwhile, Britney`s conservatorship is set to remain in place for the rest of the year.
A source recently explained: "The conservatorship won`t be ending this year because everything is going well.
"Britney is on tour again, which she truly loves. This would be the worst time to make a change, while she is on the road, and is in unfamiliar surroundings.
"There is just no reason for the conservatorship to end this year. The worst thing that could happen is that it ends, and Britney reverts back to her old ways, that would truly gut Jamie."