Introduction: Approximately 88% of men and 79% of women with Parkinson's disease (PD) identify an informal caregiver. Although caregivers can play a key role in supporting patients, little is known about how and whether PD patients with and without caregivers differ in terms of physical, cognitive, and mood outcomes. This study explored whether caregiver presence was associated with variations in patient presentation and outcomes in a palliative PD and atypical PD population. Methods: Secondary data on individuals with PD and their caregivers came from baseline data of a 3-site randomized controlled trial of outpatient palliative care for PD in the US and Canada. Measures included: MDS UPDRS III, Montreal Cognitive Assessment, quality of life (QOL) measures, depression, prolonged grief, spirituality (FACIT SP-12) and Palliative Performance Scale. Results: Of 210 participants, 175 (83%) had a caregiver. Patients with caregivers had greater motor difficulty, lower cognitive scores, and greater palliative needs as measured by the Palliative Performance Scale. Despite poorer cognitive and motor function, those with caregivers had higher QOL as measured by the Quality of Life in Alzheimer Disease and less spiritual distress. There were no group differences on anxiety, depression, or grief. Caregiver presence moderated the association between lower MoCA score and worse motor symptoms. Conclusion: Findings of the present study highlight the influence of caregiver engagement on PD patient outcomes. These findings have implications for clinical practice and suggest that presence of a caregiver may be an important modifying variable on patient outcomes to examine in future research.