Clusterin is a widely distributed glycoprotein with a wide range of biologic properties. A prominent and defining feature of clusterin is its marked induction in such disease states as glomerulonephritis, cystic renal disease, renal tubular injury, neurodegenerative conditions, atherosclerosis, and myocardial infarction. The expression of clusterin in these states is intriguing given the apparent incongruity of the conditions listed, the variety of stimuli eliciting such expression, and the multiple proposed roles once induced. This review will outline the conditions associated with clusterin induction and speculate on its role in disease.