The United States Senate will vote today on an amendment to the administration's new tax bill providing a tax credit of up to $325 for parents or others paying the tuition of college students.

Senator Abraham D. Ribicoff (D-Conn.) introduced the amendment to the $6 billion tax bill. It would allow anyone paying a student's college tuition to subtract as much as $325 from the taxes he would otherwise pay.

James A. Dorsch, Ribicoff's legislative assistant, said yesterday that the vote on the bill would be close. "This will be a real cliffhanger. In one count of the votes we get 44-45," he added, and in another we get 45-44."

The administration is opposed to the amendment. Dorsch also noted that Senators Edward M. Kennedy '54 (D-Mass.) and Leverett Saltonstall '14 (R-Mass.) are expected to vote against it.

Under provisions of the amendment, anyone who pays a student's tuition could subtract 75 per cent of the first $200 of college costs, 25 per cent of the next $300, and 10 per cent of the next $1000 from his tax liability. The amendment considers college costs to include tuition, fees, books, and supplies.

Earlier Amendment

The amendment is the same as the one Ribicoff proposed for the 1964 tax reduction bill. The earlier amendment was defeated 48-45. The present amendment was rejected by the Senate Finance Committee 7-4, but was introduced again on the floor of the Senate.

War Revenues

The cost of the tax credit to the treasury has been estimated at $ 1 billion a year. Ribicoff pointed out in a speech Friday that since the credit would first be available on the returns submitted in 1968, it would not affect the amount of revenue raised for the Vietnam during 1966 or 1967.

The amendment will probably be deleted in the Senate-House conference to iron out differences in the versions of the bill. Dorsch said that they are "worrying about first things first. We still have to get it through the Senate."