Patients with chronic pain often report negative and aversive rumination about pain and its consequences. Little is known about how and why patients with chronic pain worry. This study provides a description of worrying by chronic pain patients. Eighteen female and 16 male chronic pain patients reported, over a 7-day period, their experience of pain-related and non-pain-related worry. Results indicated that, in comparison with non-pain related worry, worry about chronic pain is experienced as more difficult to dismiss, more distracting, more attention grabbing, more intrusive, more distressing and less pleasant. Further analyses suggest that these characteristics of worry about chronic pain do not arise from a general disposition to worry or from a general disposition to anxiety. Worry is, however, related to awareness of somatic sensations. These results are discussed within an attentional model in which worry functions to maintain vigilance to threat.