No, it does not matter. The deduction is available for both undergraduate and graduate student loans.
Here is a link to IRS Publication 970 which has a section (page 29) on the Student Loan Deduction and covers all its aspects: https://www.irs.gov/pub/irs-pdf/p970.pdf.
The deduction is limited to $2500 of interest paid, and there are adjusted gross income phase-out ranges depending on filing status.
