Depression and sleep are important clinical accompaniments influencing quality of life. The cause-effect relationship of PD and depression is debatable: it may be reaction to underlying disease or intrinsic to the disease because of neurotransmitter alternatives such as decrease in dopamine, noradrenaline and serotonin. Similarly sleep disorders in PD may be intrinsic to the disease or may be iatrogenic. It has important implication in activity of daily living. The readers will be benefited from a critical analysis of these two non-motor manifestations.