An experiment with 44 participants assessed the moderating effects of four levels of incentive value on cardiovascular responses in active coping. Randomly assigned to one of four different incentive conditions, participants performed a memory task without knowing its difficulty in advance. By means of successfully performing the task participants could either win no reward, 10 Swiss Francs, 20 Swiss Francs, or 30 Swiss Francs. In accordance with the theoretical predictions derived from motivational intensity theory, reactivity of systolic blood pressure and heart rate monotonically increased with incentive value. Thereby, these findings provide additional empirical evidence for the predictions of motivational intensity theory with regard to unclear task difficulty and extend recent research (Richter, M., Gendolla, G.H.E., 2006. Incentive effects on cardiovascular reactivity in active coping with unclear task difficulty. Int. J. Psychophysiol. 61, 216–225.), which was not conclusive regarding the predicted monotonic relationship between incentive value and cardiovascular reactivity under conditions of unclear task difficulty.