The 53-year-old was last seen at Southern Cross Railway Station at around 11:20 am today, boarding a train on the Upfield line.
Police and family have concerns for Maria due to her being a person with a disability and non-verbal.
Police have released an image of Maria in the hope someone recognises her and can provide information on her whereabouts.
Maria is described as Caucasian, slim, with short grey hair.
She is wearing a black puffer jacket, dark blue jeans, white Lacoste shoes and carrying a black shoulder bag.
Anyone who sees Maria or may have information on her whereabouts is urged to contact Footscray Police Station on (03) 8398 9800.
