Having moved their first determining step from Stage II in 2004 (Saturday 24 April 2004 ) to Stage III in 2008 (Saturday 3 May 2008), Guam receives a 30% Bonus in at-large delegate votes (+1 at-large). Total delegate votes changes from 8 to 9.

Saturday 3 May 2008: A Territorial Caucus meets to choose 8 of Guam's 13 delegates to the Democratic National Convention (together representing 4 of Guam's 9 delegate votes at the National Convention). Guam's caucus is conducted like a party-run primary where voters cast secret ballots in their respective precincts. Polls open at 10 a.m and close at 8 p.m. local time (UTC+10 hours). A mandatory 15 percent threshold is required in order for a presidential contender to be allocated National Convention delegates.

• These 8 at-large delegates to the National Convention are allocated to the presidential contenders in a way which reflects the percentage of support for the candidates at the Territorial Caucus.
• Each of these 8 pledged delegates will only cast ½ (or 0.5) of a vote on the floor of the Democratic National Convention.

The village of Inarajan is celebrating the Feast of St. Joseph on 3 May. They cast their ballots on 26 April.

The remaining 5 delegates (representing Guam's remaining 5 delegate votes) are Unpledged PLEOs who will go to the Democratic National Convention officially "Unpledged".

• This territory's Democratic Member of Congress (Territorial Delegate Madeleine Z. Bordallo) (=a non-voting Delegate in the House of Representatives); the territorial Delegate is an "Unpledged PLEO" and casts 1 delegate vote.
• This territory's 4 Democratic National Committee members: each of these territorial DNC members casts 1 vote apiece for a total of 4 delegate votes.