Parkinson's disease (PD) is second most common neurodegenerative disorder after Alzheimer's disease that may present with both motor and non-motor symptoms (NMSs). Many of the ignored NMSs may potentiate further deterioration of the patient's quality of life (QoL). But there is scarcity of data regarding NMSs of PD patients and their relationship with the disease severity in Bangladesh. This study was aimed to investigate the frequency of NMSs and assess their debatable impact on the severity of PD patients in Bangladesh. This cross-sectional type of observational study was conducted in neurology department of Dhaka Medical College Hospital, Bangladesh from January 2012 to June 2013 which recruited 60 eligible PD patients. The PD patients and disease severity was demonstrated by UK Parkinson's Disease Society Brain Bank criteria for idiopathic PD and the Hoehn and Yahr scale respectively. Whereas, NMSs were demonstrated by the self-structured questionnaire which had encountered 30 common symptoms of PD. The mean age of our study cohort was found 57.88±10.56 years with male female ration 2:1. According to the Hoehn and Yahr (H & Y) severity scale 38.3%, 38.3%, 20.1% and 3.3% patients had been suffering from stage ?, stage II, stage III and stage ?V Parkinson's disease respectively. Irrespective of the severity of the PD the frequency of NMSs was nocturia (66.7%), sadness or blues (65.0%), memory disturbance (61.7%), anxiety (58.3%), insomnia (56.7%), orthostatic hypotension (55.0%), erectile dysfunction (50.0%), urinary urgency (46.7%), anhedonia (45.0%), olfactory disturbance (38.3%), constipation (38.3%), hyper or hypo sexuality (31.7%) and restless leg syndrome (31.7%). However, after head-to-head NMSs analysis, daytime dribbling of saliva (p=0.024), urinary urgency (p=0.036), nocturia (p=0.001), weight loss (p=0.001), anhedonia (p=0.027), excessive daytime sleepiness (p=0.024), insomnia (p=0.007), vivid dream (p=0.024), REM behavior disorder (p=0.010), restless leg syndrome/ periodic leg movements (p=0.043) had significantly been reported higher among the stage II PD patients than that of stage I patients. Whereas fall (p=0.001), dysphagia or choking (p=0.002), constipation (p=0.003), fecal incontinence (p=0.033), excessive daytime sleepiness (p=0.033), anxiety (p=0.036) and anhedonia (p=0.044) were significantly more prevalent among the advanced stage (III) than stage (II) PD patients. Mean total NMS increased significantly with PD severity based on H and Y staging with a mean NMSQ-T (Non-Motor Symptoms Questionnaire Test) of 5.43 in stage 1, 9.22 in stage 2, 13.75 in stage 3 and 17.0 in stage 4 (p=0.0001). This study revealed that there was high frequency of NMSs among the PD patients and most common symptoms were nocturia, sadness, memory impairment, anxiety, insomnia, orthostatic hypotension, erectile dysfunction, anhedonia, urinary urgency and constipation. Finally, the more advanced disease as indicated by a higher H&Y stage was associated with significantly higher number of reported NMSs.