Biological and behavioral mediators link Type D personality with a poor prognosis in heart disease. However, the mediator role of cognitive biases is still unknown. This study tested whether Type D individuals exhibit an interpretative bias for ambiguous social situations. For this aim we examined Type D and non-Type D individuals' evaluations of written social situations that varied in terms of situations' clarity (clear, ambiguous) and social judgment (neutral, negative). A convenience sample of 42 young, healthy adults rated each situation in relation to the difficulty of formulating a verbal response, anticipated distress, and perceived threat, and they completed the Type D personality scale (DS14; Denollet, 2005). Results showed an interpretation bias among Type D individuals, as they rated ambiguous or neutral situations as significantly more distressing compared to non-Type D individuals. Only clearly negative situations were rated similarly by Type D and non-Type D individuals. The discussion suggests that this interpretation bias in Type D individuals would increase their vulnerability to perceived stress.