Police say an 83-year-old Greenfields woman may have been laying in a creek for over 24 hours before she was found by SES volunteers.
Margaret Lowden, who has dementia, walked off from her retirement home on Legend Crescent on Wednesday morning.
A land and air search begun at 7.30am on Friday and after three hours she was found by SES volunteers laying in a creek in bushland off Old Pinjarra Road.
Mrs Lowden was taken by ambulance to Peel Health Campus.
Police say she appears to be in reasonably good health despite being missing for 48 hours.