Veterinary visits are known to be stressful for many dogs. The aim of this study was to assess dog welfare in the waiting room of the veterinary clinic through a multi-modal, non-invasive approach. Forty-five dogs were each videoed for 3 min in the waiting room of a veterinary clinic where they went for a scheduled visit. The welfare of each dog was assessed using a thorough video analysis and two overall evaluations (low, medium and high stress); one performed by a veterinary behaviourist and one by the dog's owner. Two-thirds of dogs spent more than 20% of the time displaying at least one indicator of stress, and 53.3% showed four or more behavioural signs of stress. Assessments of stress by the behaviourist indicated that level of stress in the waiting room was high in 28.9% of cases. The agreement between owners' and behaviourist's overall evaluations was quite low. The behaviourist's evaluations were strongly correlated with the time spent by dogs showing signs of stress and moderately correlated with the number of displayed signs, whilst owners' evaluations were not closely correlated to those factors. Dogs rated as highly stressed by the behaviourist were more prone to display resistance (halting, refusing to budge) when moving from the waiting room to the consultation room. The results of this pilot study support the idea that the welfare of dogs in the veterinary waiting room is often impaired, and that owners are unable to accurately assess stress in their dogs in such situations