Parkinson s Disease (PD) is characterized by the occurrence of motor symptoms. However, non motor symptoms such as depression and cognitive impairment are common and should not be ignored. This thesis investigated the frequency of depressive symptoms and their effect on cognition in individuals with PD with mild cognitive impairment (MCI). Forty eight subjects with PD and 44 controls (CG), aged between 50 and 80 years and higher education to four years, all with MCI and undiagnosed depression were studied. The participants underwent clinical evaluation with a neurologist, followed by neuropsychological assessment. Depressive symptoms were measured using the Beck Depression Inventory. Difficulty in work, fatigue and sleep disorders were more frequent symptoms in PD group, whereas the group without PD presented beyond sleep disorders, symptoms of irritability, and decreased libido. The presence of these symptoms was found to be associated with loss of attention combined to episodic memory deficits, especially in recognition tasks of new verbal information. The prevalent depressive symptoms in parkinsonians with MCI can be attributed to PD, complicating the differential diagnosis between these conditions.