Previous studies of speech dysfunction in patients with Parkinson's disease (PD) consisted of postal surveys, which rely on the subjective opinions of patients, or were primarily focused on the detailed assessment of impairments without addressing the disabilities resulting from them. Similarly, the impact of the communication disability on the patient's everyday life was not assessed. The aim of the present study was to examine the prevalence of verbal communication disability in these patients, using a validated objective measurement tool. A secondary aim was to establish the patients' awareness of their disability and its impact on their lifestyle. Verbal communication disability was examined in 48 patients with PD using a modified version of the Intelligibility of Dysarthric Speech Assessment Scale. Nearly two-thirds of patients had reduced intelligibility of speech but this was mild, causing no disability, in the majority of them. Two out of seven patients with severely or moderately severely reduced intelligibility of speech were unaware of their disability, and none of the patients reported that the speech difficulties interfered with their lifestyle. The study also identified some predictors of verbal communication disability in these patients.