Members of the DNC elect a chair at their first meeting early next year, probably late January or early February.
http://www.democrats.org/about/function.htmlMembers of the Committee
While anyone who is registered to vote as a Democrat is a member of the Party, there are 440 members of the Democratic National Committee.
The National Committee has 9 elected officers: The Chair, five Vice Chairs, Treasurer, Secretary, and National Finance Chair.
Membership on the National Committee is composed of individuals selected by the Democratic Party organizations in each state (including the District of Columbia and Puerto Rico), the U.S. Territories (American Samoa, Guam, and the Virgin Islands), and Democrats living outside the United States and those Territories listed above (Democrats Abroad).
Each jurisdiction is represented by its Chair and the next highest ranking officer of the opposite sex. An additional 200 votes are distributed to the states and territories based on population, with each receiving a minimum of two additional seats. Each delegation must be equally divided between men and women.
Also seated on the DNC are representatives of various Democratic constituencies and elected officials. These include two U.S. Senators and U.S. Representatives, two members of the College Democrats, and three representatives each from the Democratic Governors, Mayors, State Legislators, County Officials. Municipal Officials, Young Democrats, and the National Federation of Democratic Women. Fifty members are appointed by the DNC Chairmen, and approved by the DNC, and are considered "Members-at-Large."