Depression in idiopathic Parkinson's disease is highly prevalent that can significantly impair the quality of life. Its exact mechanism of development is still poorly understood. It is well studied in western population but data from Asia especially in the South Asian region is limited. Considering this, to identify the potential risk factors of depression, a cross-sectional study was conducted among Parkinson's disease patients attending a tertiary care hospital in Bangladesh between July 2013-June 2014, in the Department of Neurology, Shaheed Suhrawardy Medical College and Hospital in Dhaka, Bangladesh. One hundred thirty seven cases of Parkinson's disease were enrolled, based on UK Parkinson's Disease Society Brain Bank criteria. Brain MRI was done in all cases, and patients with aphasia, significant cognitive deficits, secondary Parkinsonism were excluded. The overall prevalence of depression in the study population was 42%. There were no significant differences in gender, residence, education, smoking and marital status. In univariate analysis, age≥70 years, un-employed, right side predominantly involved, disease duration ≥5 years, sleep disturbance, postural instability, dose of levodopa ≥500 mg/day, Hoehn and Yahr stage ≥III and moderate to severe disability were significantly associated with depressive disorder. Whereas in multivariate linear stepwise regression model, age ≥70 years, (p=0.044), right side predominant involvement (p<0.001); sleep disturbance (p=0.006) and dose of levodopa ≥500 mg/day (p<0.001) were the major risk factors for depressive disorder. A significant proportion of Parkinson's disease patients suffer from depression. It was identified that depression in Parkinson's disease was significantly associated with advancing age, predominate right side involvement, sleep disturbance and higher daily dose of levodopa.