Stewart, 46, left The Lowry where he works approximately 1pm on Tuesday (30 October 2018) but no-one has heard from him since yesterday.
He is white, around 5ft 10in tall, of medium build with short, blonde hair.
Officers believe Stewart might be wearing a dark coloured raincoat with a dark coloured top and bottoms.
He lives and works in Salford but has links to the Bath and Norfolk area.
Police Sergeant Clare Hall of GMP’s Salford Borough, said:
“It’s not like Stewart to not have contact with anyone for such a long period of time and, as the hours go on, we’re getting more and more concerned for his safety.
“If you’ve seen him since Tuesday or know where he may be, please get in touch with us as soon as you can so we can bring him home safely.”
Anyone who sees Stewart or knows where he is can contact the local team on 0161 856 2836.