Study Design. The design of the study was prospective and correlational. Objectives. The aim was to investigate a mediating function of copingbetween self-efficacy and disability as well as changes in this model over a one-year period in patients with Whiplash Associated Disorders(WAD). Summary of Background Data. The central part of the pain problems is patients' beliefs about pain as well as coping with conditions related to pain. Methods. Fifty-nine patients with WAD, 35 females and 24 males visiting the orthopaedic clinic took part in the study. Patients were studied prospectively on three occasions, at inclusion, at six- and 12-month follow-ups. Three measures were used in the study, the Self-EfficacyScale, the Coping Strategies Questionnaire and the Pain Disability Index. Path analyses were used to analyse the data and test models for themediating function of coping. Results. The results of the path analyses supported the mediating role of coping between self-efficacy anddisability. The direct effect of self-efficacy decreased from 97%, 93% to 67% of the total effect on disability over time. The indirect effect ofcoping on disability increased from 3%, 7% to 33% during the first year after the accident. Conclusions. It was concluded that the lack of belief inone's own ability, i.e., self-efficacy may predict the use of different coping strategies which in turn may predict the extent to which individuals with WAD become disabled.