Police are appealing for public assistance to help locate missing Ferntree Gully woman Clare Ross.
Clare left her home address on Lording Street about 9.40am on Sunday 30 August.
Police and family hold concerns for her due to a medical condition.
The 78-year-old is believed to have been in the vicinity of Quarry Road where her car and mobile phone were located just before 9pm.
Investigators have released an image of Clare in the hope that someone may have information on her current whereabouts.
Anyone who sees Clare is urged to contact Knox Police Station on 9881 7000.