The anticipation of regret is known to be a primary motivator of receiving a vaccination. Aim of this study is to evaluate whether the use of messages that leverage the anticipated emotion of regret can increase the intention to get the flu vaccination. The participants (N = 110) randomly received a leaflet containing a standard prevention message (control condition) or message modified to induce the anticipation of regret over not being vaccinated (experimental condition), along with a questionnaire. The experimental condition’s participants reported significantly higher levels of regret and higher intention to vaccinate than the participants in the control condition. Anticipated regret resulted to be a significant mediator of the intention to get vaccinated. Manipulating the salience of regret appears to be a simple and inexpensive way of effectively promoting preventive behaviour. The implications of this result for reducing COVID-19 vaccine hesitation are discussed.