Double-labelling immunohistochemistry of Bcl-2 and Bax, and ubiquitin (as a marker of Lewy bodies) was examined in the brains of patients with Parkinson's disease and Diffuse Lewy body disease to learn about possible modifications of protein expression and the presence of Lewy bodies. Bcl-2 and Bax immunoreactivities were observed in Lewy body-bearing and non-Lewy body-bearing neurons in patients with parkinsonism. These results show that Bcl-2 and Bax are probably not implicated in Lewy body formation and that the presence of Lewy bodies does not have a direct impact on the expression of Bcl-2 and Bax proteins in individual neurons.