The debate, emanating from Las Vegas, airs at 8:30 p.m. on CNN and will be moderated by Anderson Cooper.
The former secretary of state, senator and first lady, will be debating Vermont Sen. Bernie Sanders, former Maryland Gov. Martin O'Malley, former Rhode Island Gov. Lincoln Chafee and former Virginia Sen. Jim Webb.
Clinton is the Democratic frontrunner for the nomination though Sanders has been cutting into her lead in recent polls as Clinton has been dogged by her admission of using a private server for her e-mails while she was secretary of state.
According to NBC News, Clinton's two goals at the debate are to demonstrate she is the best Democrat on the stage to be president and to exude passion and show she is a policy wonk.
Tuesday's debate is the first of six scheduled Democratic presidential debates.
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