Due to the increasing amount of automation in vehicles, the role of the driver changes from having an active part in the driving of the vehicle, to a reactive monitoring task. This change might be relevant to the comfort experienced by the driver. But how can this comfort be assessed? Generally, comfort can be defined as a mood, being pleasant but not especially aroused. Literature proposes measuring discomfort instead of comfort since it is a deviation from the normal state and therefore easier to notice. Since currently there is no subjective questionnaire to measure discomfort in Human‐Machine Interaction (HMI), we developed a 14‐item scale to measure discomfort of the driver ‐as an indicator for the absence of comfort ‐ considering the following aspects: Discomfort, demands, risk, and loss of control. The questionnaire was applied in an explorative driving simulator study analysing crucial aspects of future automation. In this experimental study, the distance between the automated vehicle and another vehicle driving ahead was varied in different driving situations. The internal consistency of the questionnaire was high (r = .91). A first validation of the questionnaire was conducted on the basis of driving behaviour and the reliance on the automation. Results suggest that this questionnaire is a useful tool for assessing discomfort in the automated HMI. This first version is focused on, but not limited to, automation and advanced driver assistance in vehicles. A generalisation of the scale for further research, as well as for applied issues, will be discussed.