84-year-old Mubarak fell in the bathroom of his hospital room, state-run MENA news agency quoted a security source in the Prisons Authority as saying.
A medical team supervising his condition attended him immediately, the source said, adding that Mubarak has suffered head injury and bruising. The source, however, did not disclose when the incident took place.
Mubarak is currently serving a life sentence in Tora prison hospital for not preventing the murder of protesters during the last year's popular uprising against his regime.
The former strongman who ruled Egypt with an iron-fist occupying the sprawling presidential palace in Cairo for nearly three decades from 1981 to 2011 was ousted after 18 days of demonstrations during the revolution.
On 2 June 2012, Mubarak was sentenced to life imprisonment by an Egyptian court which convicted him of complicity in the murder of protesters during the uprising.
After sentencing, his health condition deteriorated and he suffered a series of health crises, including a stroke.
