The aim of the present study was to assess the various patterns of sleep disturbances in Parkinson's Disease and to compare the polygraphic sleep measures in both treated and untreated parkinsonian patients and healthy age-matched controls. Our study included 30 patients all diagnosed as Idiopathic Parkinson's Disease, the patient group was divided according to their medications into two subgroups: Subgroup I included patients not on treatment and Subgroup II included patients on treatment.All subjects were evaluated through history taking, medical & neurological examination, routine laboratory tests and neuroradiological imaging CT / MRI. The clinical disability of the PD patients was graded using The Unified Parkinson Disease Rating scale and The modified Hoen and Yahr scale and sleep disorders were eavaluted using Parkinson's Disease Sleep Scale and The Epworth Sleepiness Scale, in addition to Plysomnography Recording.36.7% of our patients had positive sleep complaint, while 63% had abnormal scores on detailed sleep questionnaire suggesting that sleep disturbance may be under estimated by the PD patients. While, 27% of the PD patients complained from Excessive Daytime Somnolence, none of the control group had abnormal ESS scores. Polysomnographic features of our PD patients when compared to controls showed Reduced sleep efficacy and Higher A/H index in the PD patients. The patients with predominant bradykinesia, had a significant higher Apnea/Hypopnea Index than those with predominant tremors implying that respiratory muscle dysfunction is more common with those suffering from bradykinesia. The degree of sleep disturbance increased with age and was significantly higher in males, this shows a clear impact of the socio-demographic variables on sleep parameters.No statistically significant difference was detected between the PD patients not on medication and those receiving L-dopa treatment, suggesting that sleep disturbances in PD patients may be primarily related to its pathological process. On the other hand, higher doses of L-dopa was associated with better sleep quality in the PD patients.Conclusion: The cause for sleep disorders in PD is multifactorial: it is partially related to the disease, its symptoms, in addition to the age and related co morbid conditions, and medications used. However beneficial effect of L-dopa on the disturbing nocturnal motor manifestations of parkinsonism will outweigh the adverse effects on sleep.