Police are appealing for information to find missing man Steve who has non-verbal autism.
The 41-year-old was last seen at Clayton Railway Station with his carer at 10.24am this morning.
He was left alone for a short time and when his carer returned, he had disappeared.
CCTV footage shows him getting onto a bus however police are still trying to determine where the bus was headed.
Police and family are concerned for Steve's welfare as he requires full-time care.
Images of Steve have been released, including a CCTV image taken at the railway station this morning.
Steve is described as Caucasian, with a solid build, balding brown hair and a goatee.
He was last seen wearing a blue hoodie, dark tracksuit pants, blue runners, a lanyard around his neck containing personal items and carrying a grey bag.
Anyone with information on Steve's whereabouts is urged to contact Oakleigh Police Station on (03) 9567 8900.