Mujahid Nadeem, 24, was last seen leaving Jazzy's Newsagents in Paisley's Netherhill Road at around 9.45am on Saturday.
He is described as 6ft tall with a slim build with cropped dark hair.
He is clean shaven and has a birth deformity of both arms.
When last seen he was wearing a black, deer stalker-style hat, black jacket, blue jeans and white firetrap trainers.
Inspector Stuart Thomson from Police Scotland said: "Mr Nadeem worked in Jazzy's Newsagents and left the shop unattended for no apparent reason.
"He headed off in the opposite direction of his home which is in St Margarets Avenue, Paisley.
"Mujahid is considered vulnerable due to the deformity of his arms.
"As time goes by, we are becoming increasingly concerned for his safety and wellbeing.
"He is known to frequent casinos and extensive enquiries have been ongoing to find him to make sure he is okay.
"Although he has left home before, he has not been missing for more than 24 hours."
Any person who has seen Mujahid or has any information regarding his whereabouts is asked to telephone police on the non emergency telephone number 101.