Emma Greaves, 28, was last seen leaving The Arc Light Centre on Haxby Road, at 7.15pm on Thursday 19 July 2012.
She is described as a white, slim build, around 5ft 3in tall, shoulder length dark hair tied back using a white bobble. She was wearing a black jacket, black trousers and a blue scarf.
Emma is possibly in the company of Robert Edeson, who is currently wanted by North Yorkshire Police for breaching his court bail conditions for an alleged assault.
He is white, aged 30, with short brown hair, slim build and around 5ft 7in tall. He was last seen during the afternoon of Thursday 19 July 2012 and is believed to be wearing white trainers, grey jogging bottoms, black jumper and a beige jacket.
Police are appealing for any information or possible sightings that could help locate Emma Greaves and Robert Edeson.
If you can help please call North Yorkshire Police immediately on 101 and press option 1 to speak to the Force Control Room.
Information can also be passed on anonymously to Crimestoppers on 0800 555 111, please quote reference NYP-19072012-0620.