Research shows that the frequency of magical thinking and superstitious behavior increases under conditions of stress. A possible explanation for this finding is that stress reduces the individual's sense of control and that to regain control she or he engages in magical rituals or superstitions. This study tested the validity of this explanation. To this end, the effects of stress on the frequency of superstitious behavior in individuals with high and low desire for control (DC) were examined. The Desirability of Control Scale was administered to 108 participants, half of whom were exposed to low-stress conditions and half to high-stress conditions. They were interviewed and asked questions designed to elicit a "knock on wood" ritual. It was found that the difference in the number of knocks on wood between high-DC and low-DC individuals was greater in the high-stress than in the lout-stress condition. Similar findings emerged when the degree of the need to knock on wood, as reported by the participants, was used as a dependent variable.