Non-motor symptoms (NMS) are common in Parkinson's disease (PD) and are considered the most disturbing symptoms to both patients and caregivers. Sleep disorders including rapid-eye-movement sleep behavior disorder (RBD), obstructive sleep apnea (OSA), restless legs syndrome (RLS), and periodic limb movement in sleep (PLMS) are common in and contribute to the disability of PD patients. This study evaluated the impact of sleep disorders on the NMS of PD. Eighty-six PD patients were evaluated and assessed for sleep disorders, sleepiness and the multiple NMS of PD. Principal component analyses and hierarchical multiple regression analyses were used to assess the relationship between the different NMS and the existence of sleep disorders. Results showed that sleep disorders are significant contributors to NMS in PD (p<0.001) with age (p=0.011), dopaminergic therapy (p=0.013), RBD (p=0.008), and RLS (p=0.013) as significant predictors of the NMS score. Additionally, having sleep disorders (i.e., RBD, RLS, OSA) significantly predicted reported nighttime sleep dysfunction (p<0.001), poor mood (p=0.002), increased fatigue (p=0.001), and reduced quality of life (p<0.001). However, having a sleep disorder did not significantly predict subjective or objective daytime sleepiness. In summary, this study showed that in the PD patient population, the presence of co-morbid sleep disorders predicts more NMS symptoms in general. More specifically, having sleep disorders (i.e., RBD, RLS, OSA) predicted increased reports of nighttime sleep dysfunction, poor mood, lower quality of life, and increased fatigue in this sample of PD patients. Of the sleep disorders assessed in this study, RBD and RLS were indicators of increased NMS but OSA was not. Further studies are now necessary to indicate if treatment of these sleep disorders will result in improved NMS and improved quality of life for PD patients and their caregivers.