The symptoms of Parkinson's disease (PD) often include motoric changes due to increased muscle rigidity. This may impact the speech and swallowing abilities of those diagnosed. Examining bolus size during swallowing may provide more conclusive evidence regarding swallowing behaviors, particularly the oral phase, during on and off-phase symptom control. This study proposed an assessment of the typical liquid bolus size in free cup swallows of those diagnosed with PD. In order to assess the effect of on and off-phase on the participants bolus size, participants were asked to perform a free cup swallow approximately thirty times during a session, a single swallow occurring between each speech assessment task (diadochokinetic rates and prolonged ah's). The amount of water the participants swallowed was measured post-swallow and this was recorded. Two sessions were conducted during the patients' self-identified on-phase (when they considered their motor symptoms to be reduced) and twosessions during their self-identified off-phase (when they considered their motor symptoms to be exacerbated). Comparing on and off-phase performance is of interest, as individuals with PD may try to organize meals and/or communication activities around administration of their medications and times when they feel their motoric symptoms are minimized.