Test anxiety is prevalent among adolescents. Some potentially successful mindfulness-based coloring interventions have been identified in previous research, however, conclusions have been based on self-report measures only. In the current study, 150 17- to 18-years-olds taking final school exam completed measures of state anxiety (STAI) and Mindfulness (SMS) prior to and directly after completing 12 min of either (1) free drawing, (2) mandala coloring, (3) mandala coloring paired with pre-recorded mindfulness instructions. Heart rate (HR) was recorded prior to and directly after the 12-min coloring intervention.