Background: Psoriasis is a chronic inflammatory immunologically mediated disease characterized by antigen presentation and keratinocytes hyperproliferation due to release of chemokines and cytokines from activated T-lymphocytes. Relationship between psoriasis and peripheral vascular diseases, increased risk of myocardial infarction and cerebrovascular diseases has been reported. Clusterin [apolipoprotein J] is a 75-80 KDa disulfide-linked heterodimeric protein associated with apoptosis and clearance of cellular debris. Clusterin [CLU] is involved in many diseases related to oxidative stress, including neurodegenerative and inflammatory diseases. Aim of the work: The aim of this study is to estimate the serum level of clusterin in patients with severe plaque psoriasis to evaluate its possible role in psoriasis pathogenesis and comorbidity. Patients and methods: Sixty patients with severe plaque psoriasis having Psoriasis Area Severity Index [PASI] score more than 10 and Thirty healthy individuals as control were studied by enzyme linked immunosorbent assay for determination of serum clusterin levels. Results: Serum levels of clusterin showed statistically significant increase in psoriatic patients than in controls. Conclusion: Psoriatic patients show increase clusterin serum level compared with normal controls. This indicates that it may have a potential role in the pathogenesis of psoriasis and may be related to increase risk of cardiovascular diseases among psoriatic patients.