Over the last few years there has been increased interest in worry. Most assessment up until now has been concerned with what people worry about and how much they worry rather than exploring reasons for worrying. Two questionnaires were developed to go beyond the content and intensity of worry. The first questionnaire, Why Worry?, contains 20 items and assesses reasons why people say they worry. Two types of reasons were found. First, subjects believe that worrying can prevent negative outcomes from happening, minimize the effects of negative events by decreasing guilt, avoiding disappointment, or provide distraction from thinking about things that are even worse. Second, people believe worrying has positive effects such as finding a better way of doing things, increasing control, and finding solutions. The second questionnaire, Intolerance of Uncertainty, consists of 27 items that assesses emotional, cognitive and behavioral reactions to ambiguous situations, implications of being uncertain, and attempts to control the future. The second study demonstrates the instruments' properties by distinguishing between levels of worry, by factor analysis describing the dimensions underlying the constructs, and by establishing appropriate relationships with measures of worry and emotional distress. The implications for current models of worry are discussed.