The objective of this study was to take a closer look at defense-related expenses for medical malpractice cases over time. We conducted a retrospective review of medical malpractice claims reported to the Physician Insurers Association of America's Data Sharing Project with a closing date between January 1, 1985 and December 31, 2008. On average a medical malpractice claim costs more than $27,000 to defend. Claims that go to trial are much more costly to defend than are those that are dropped, withdrawn, or dismissed. However, since the overwhelming majority of claims are dropped, withdrawn, or dismissed, the total amount spent to defend them surpasses that spent on claims that go to trial. Defense attorney expenses account for the majority of defense-related expenses (74%), while expert witness expenses and other expenses split the remaining 26%. A strong association was also found between the average indemnity payment and the amount it costs to defend individual claims by specialty. Our study found that defense-related expenses for medical malpractice claims are not an insignificant cost. As state and federal governments debate how to repair the malpractice system, addressing the high cost of defending claims should not be ignored.