A Democratic source tells C-N-N that the powerful Senate Appropriations Committee chair held by Inouye will now be taken over by Senator Patrick Leahy of Vermont.
Leahy is chair of the Senate Judiciary Committee, a seat that will now be taken over by Senator Dianne Feinstein of California.
The Judiciary committee has oversight on gun control laws, a cause that Feinstein has fought for.
It is not clear who will take over her role as chair of the Senate Intelligence Committee.
With Inouye's death, Leahy becomes the most senior Democratic senator, the President Pro Tempore.
Vice President Joe Biden swore Leahy in Tuesday.
This means he is third in line to the presidency, after Biden and House Speaker John Boehner.