Graduate students qualify for many federal and private educational loan programs. To determine eligibility for federal programs, a student must complete a Free Application for Federal Student Aid (FAFSA).
First-time borrowers in the Direct Loan program must also complete Entrance Loan Counseling and a Master Promissory Note. Please be aware that graduate students are not eligible for subsidized student loans.
Under some conditions, payments on previous (e.g. undergraduate) student loans may be deferred while in graduate school. You can find good information and see if you're eligible for a deferment at the U.S. Department of Education site on Stafford Loans.