The possible role of iron in the degeneration of nervous cells in Parkinson's disease (PD) was studied with the use of Mössbauer spectroscopy (MS) and enzyme-linked immunoabsorbent assay (ELISA). Mössbauer data were obtained at 90 and 4.1 K from 21 samples of control and 9 samples of parkinsonian substantia nigra (SN). Mössbauer spectra were very similar to those observed in ferritin. Small differences were detected between the spectra obtained from PD and from control SN, and could be due to a slight difference in the composition of the ferritin-like iron cores or due to the presence of about 8% of non-ferritin-like iron in parkinsonian SN. ELISA studies from 11 controls and 6 parkinsonian SN showed a decrease in the concentration of L-chains in wet tissues of PD-SN compared to control SN. The decrease in the amount of L subunits may correspond to a decreased ability of this ferritin to keep iron in a safe form. Iron released from ferritin or neuromelanin (NM) may be the source of such iron, which may cause the difference in the Mössbauer spectra and may trigger oxidative stress leading to cell death.