"Aarushi's cellphone was recovered by Delhi Police's Crime Branch and handed over to the CBI," Delhi Police Spokesman Rajan Bhagat said.
The phone, which could be a critical piece of evidence in the probe, was recovered from Uttar Pradesh's Bulandshahr town.
A woman who once worked as maid for the Talwar family had passed it on to a resident of the Uttar Pradesh town, said Bulandshahr Superintendent of Police (City) JK Sahi.
Aarushi Talwar was found murdered in her parents' residence in May 2008. A day after her body was recovered, the body of the domestic help Hemraj was found on the terrace of the house.