Karen Winteringham, who lives in the Sun City area, was last seen on Aug. 4 in Menifee in Riverside County.
Her family says the 66-year-old suffers from dementia, high blood pressure and has heart complications. Her family is worried that she has not taken any of her medications since she went missing.
They say she likes to walk in the Cherry Hills Plaza area.
If you have any information, the California Highway Patrol is urging you to call 911 right away.