OBJECTIVES: To collate the published evidence evaluating economic burden of co-morbidities in patients with Parkinson's disease (PD) in Germany. METHODS: A systematic search of electronic literature databases (Embase® and MEDLINE®) was conducted from January 2001 to June 2012 to identify economic studies in English evaluating co-morbidities in patients with PD in Germany. RESULTS: Four studies of the 267 citations retrieved met the pre-defined inclusion criteria. During 2000-2002, direct costs were higher in patients with dyskinesias and/or motor fluctuations (€3300 [€4630]) or dementia (€3110 [€5610]) than patients without motor complications (€1450 [€3760]) or dementia (€1530 [3460]). However, indirect costs were higher for patients without dementia (€3780 [€6870]) than patients with dementia (€1080 [€4110]). In 2006, daily total costs and PD drug treatment costs decreased significantly in patients with dementia (€7.3 [7.3]; p<0.05) and depression (€6.6 [5.8]; p<0.05) than patients without dementia (€9.3 [13.9]) and depression (€7.6 [6.8]), respectively. The decrease in the costs observed across patients presenting with these co-morbidities may be attributed to the inadequate treatment of depression or dementia among patients with PD. In 2009, direct costs demonstrated a significant increase in patients with dyskinesia (€16,544 vs. €11,322; p=0.003), dementia (€21,142 vs. €10,619; p<0.001), depression (€15,904 vs. €8826; p<0.001), or psychosis (€15,398 vs. €8614; p=0.016) than patients without these co-morbidities. Indirect costs were also higher in PD patients with these co-morbidities than patients with PD alone; the difference being significant only for dementia (€8201 vs. €2964; p=0.037). CONCLUSIONS: Co-morbid dyskinesia, dementia, or depression were observed to be the major contributors to the fiscal burden of PD in Germany, post-2000. An overall increase in the (estimated) costs associated with these co-morbidities was evident during the time-period evaluated. Further studies to understand the cause of increased (estimated) costs associated with these co-morbidities in PD are warranted.