Background: The purpose of this study was to examine whether an association exists between low cholesterol level and major depression in patients with panic disorder. Methods: The subjects of the study were 16 patients panic disorder only, 16 panic disorder patients had also current major depressive episode, and 16 normal control subjects. An automated enzymatic colorimetric method was used for cholesterol determination. Results: Panic disorder patients had higher serum cholesterol than panic disorder patients with major depression and normal controls. Conclusion: There is an association between low cholesterol level and the presence of major depression in patients with panic disorder. Limitation: Future studies with large sample are needed to confirm this finding. Clinical Relevance: A low serum cholesterol level might serve as biological marker of major depression in patients panic disorder. (C) 1998 Elsevier Science B.V.