We aimed to investigate possible associations between systemic iron metabolism deficiency and Parkinson's disease, and also to research any possible correlations between stage of the disease and vitamin B12 and folic acid levels. 33 male and 27 female patients diagnosed with idiopathic Parkinson's disease and 22 male and 20 female age- and sex-matched controls were enrolled in the study. Having the diagnosis of secondary Parkinsonism or Parkinson plus syndromes, and for the females, not being in the menopausal stage were considered as exclusion criteria. Recordings of blood samples of both groups collected after 8 h fasts were assessed in terms of serum iron, ferritin levels and iron-binding capacity, vitamin B12 and folic acid levels. The Hoehn and Yahr scale was used to determine the stage of the disease. No statistically significant difference was found with respect to mean serum iron, median serum ferritin levels and median serum iron-binding capacity between the groups. A statistically significant but inverse correlation was found between symptoms' duration and serum iron and ferritin levels. There was no statistically significant difference between the groups with respect to vitamin B12 and folic acid levels. However, a statistically significant but inverse correlation was determined between the patients' vitamin B12 levels and the Hoehn and Yahr scores. As Parkinson's disease progresses, serum iron, ferritin and vitamin B12 levels may decrease. The lower levels of these parameters may be the cause of the progression or may be the result of it.