Police in Kirklees are appealing for help to track down Denise Bristol, 39, of Holmfirth.
She was last seen at her home on Field Road yesterday evening (Monday).
A West Yorkshire Police spokesperson said: "Officers are concerned for her welfare as she suffers from a medical condition.
"She is described as being around 5ft 6in tall, with black hair and was wearing black tracksuit bottoms with a white stripe.
"Denise was also wearing a chequered blue and white shirt, black shoes and a black baseball cap with a computer game controller motif."
Anyone who knows her whereabouts should call police on 101.