Related Party Transactions and Outside Related Director Information

DexCom, Inc. (DXCM)

4/12/2006 Proxy Information

Donald A. Lucas is the son of Donald L. Lucas.

From January 1, 2005 to the present, there have been no (and there are no currently proposed) transactions in which the amount involved exceeded $60,000 to which the company was (or is to be) a party and in which any executive officer, director, 5% beneficial owner of our common stock or member of the immediate family of any of the foregoing persons had (or will have) a direct or indirect material interest, except as set forth below and under “Executive Compensation.”

Our Chairman, Donald L. Lucas, retains one-half ownership in Archipelago Aviation. During the year ended December 31, 2005, we incurred costs with Archipelago Aviation totaling approximately $191,000 for airline transportation related to travel activities during our initial public offering and subsequent clinical site visits. We believe that the aforementioned arrangements were at no less favorable rates to us than those that could have been obtained from unrelated third parties based on review of price quotations with third parties.