During mindfulness-based interventions participants can beinvited to bring aversive stimuli to mind while practicingmindfulness. This is thought to help the stimuli become lessaversive. However, the mechanisms underlying this processare not fully understood. In this study we explored these byexamining the effects of mindfulness practice and stimulusvisualization on stimuli associated with electric shocks.Participants were trained on a discrimination between twovisual stimuli using a standard electrodermal conditioningprocedure, in which one stimulus (CS+) was paired withshock and the other (CS-) was not. They then visualized eitherthe CS+ or CS-, while practicing mindfulness or performing acontrol activity. Following a number of extinction trials, theimpact of these manipulations was assessed during areacquisition test-phase. Both mindfulness and visualizationof the CS+ led to slower reacquisition of the CS+/shockassociation, when measured physiologically, and their effectswere additive. Moreover, these effects dissociated fromparticipants’ expectancy of shock. If confirmed in futurework, these findings may have implications for the treatmentof stimulus-specific anxiety.