Police are trying urgently to trace vulnerable Rebecca Scott, who was last seen by a family friend around 7.45am today near her home in Deveron Road, East Kilbride.
She is described as 5ft3in tall, of medium build, with short brown hair.
When last seen she had on a bright pink waterproof jacket, black trousers and shoes and was carrying a black handbag.
She wears two hearing aids, glasses and due to a medical condition, walks slowly and uses a walking stick.
Officers have been in the area checking with friends and neighbours, local bus companies and businesses but so far there have been no further sightings of Rebecca.
Constable James Taylor, of East Kilbride Police Office, said: "Mrs Scott requires daily medication and as far as we are aware she does not have this with her and has missed her morning dose.
"The family member saw her near to Calderwood Road where it may be the case that she was heading to the bus stop.
"The number 255 and 201 buses run from there; the 201 to High Common Road, East Kilbride and the 255 to Petersburn in Airdrie via Blantyre, Hamilton and Airdrie.
"I would appeal to anyone who has seen Rebecca, especially those on the buses this morning, to contact police.
"Her jacket was quite distinctive, bright pink, and she would have been quote noticeable due to that and her reduced mobility.
"She has been missing before but is usually found nearby and has never been away for this long.
"Her friends and family are very concerned for her welfare and safety."
Information can be passed to police via the non-emergency number 101.