Falls are one of the most serious complications of gait disturbances in patients with Parkinson's disease (PD). Among previous reports, the percentage of patients with PD who fall varies between 38% to 68%. We sought to determine the frequency of falls and the factors associated with falls in a group of patients with idiopathic PD who attended an outpatient, tertiary movement disorders clinic. 350 ambulatory, non-demented patients (230 males) were studied. Mean age was 69.7+/-10.6 years (range: 43-97 yrs) and mean duration of PD symptoms was 8.6+/- 6.2 years (range: 1-33 yrs). Assessments included characterization of demographics, disease duration, disease severity as measured by the Hoehn and Yahr Scale (H&Y), co-morbidities, the presence of depressive symptoms, the presence of urinary incontinence, use of anti-parkinsonian medications, and two performance-based tests of balance and gait (tandem standing and Timed Up & Go). Fall history was determined during three time periods: previous week, previous month, and previous year. Univariate and multivariate logistic regression models were applied to evaluate the relationship between the above-mentioned factors and falls. 46% of the subjects reported at least one fall in the previous year and 33% reported 2 or more falls and were classified as Fallers. Fallers had significantly more prolonged and advanced PD compared with Non-fallers (p=0.001 and p<0.001, respectively). Urinary incontinence was the factor most closely associated with falls (crude and adjusted OR were 1.95 and 5.89, respectively). Other factors significantly associated with fall status included increased Timed Up & Go times and increased PD duration. These findings confirm that falls are a common problem among patients with advanced PD and suggest easily measurable features that may be used to prospectively identify those PD patients with the greatest risk of falls.