Assessment of anxiety in Parkinson's disease (PD) is complicated by symptoms, such as trembling and shaking, that the two disorders have in common. This symptom overlap produces a potential for overestimation of the rate and severity of anxiety when assessed by self-report questionnaire. The purpose of this study is to estimate the extent to which anxiety scores in PD patients might be overestimated by two commonly-used mood state questionnaires. Fifty-nine patients with PD were administered the Beck Anxiety Inventory and the Profile of Mood States. Results indicate that the rate of clinically significant anxiety on these measures is indeed higher than the rate of clinical anxiety as determined by interview alone, suggesting the potential for overestimation of anxiety in PD when using self-report questionnaires.