DEXCOM INC — Director's Dealing 2010

May 17, 2010

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: DEXCOM INC (DXCM)
CIK: 0001093557
Period of Report: 2010-05-13

Reporting Person: MOY JEFFREY (V. P., Operations)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2010-05-13	Common Stock	M	3593	$7.63	Acquired	71244	Direct
2010-05-13	Common Stock	M	3013	$6.33	Acquired	74257	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2010-05-13	Incentive Stock Option (right to buy)	$6.33	M	3013	Disposed	2018-09-24	Common Stock (3013)	Direct
2010-05-13	Incentive Stock Option (right to buy)	$7.63	M	3593	Disposed	2018-05-19	Common Stock (3593)	Direct

Footnotes

F1: The option vests and becomes exercisable with respect to 1/4th of the shares one year after the date of grant, and thereafter continues to vest and become exercisable as to 1/48th of the shares each month thereafter (with the shares fully vested on the 4th anniversary of the date of grant).