The move ends an embarrassing episode for the administration, which repeatedly miscalculated the needs of veterans and used outdated budget models when fashioning estimates for Congress.
The funds, which close a gap for the current budget year, were added to a $26.3 billion bill for next year's budget for the Interior Department.
The underlying budget bill generally fits within Mr. Bush's budget outlines as it cuts almost $700 million from current levels. But when Congress returns from its summer recess in September, lawmakers are sure to test the president's resolve to cut almost 1 percent from domestic agencies whose budgets Congress funds each year.
The Senate also cleared a $3.8 billion measure funding Congress' own budget.
The extra veterans funds were needed after the Veterans Affairs Department underestimated the number of veterans who would seek care as well as increased costs of treatment and long-term care.
Initially, the VA said it faced about a $1 billion shortfall that could be managed by tapping reserve funds and its budget for infrastructure improvements. That did not fly with lawmakers, who insisted on adding emergency funds on top of the $28 billion appropriated last year for veterans' medical needs.
The House originally passed legislation accepting the $1 billion estimate, but the ink on that bill was barely dry before the VA upped its estimate to $1.3 billion. The Senate twice unanimously voted for the $1.5 billion figure. The House decided to go along.
The VA's estimating models for the original budget submission did not take into account the additional cost of caring for veterans injured in Iraq and Afghanistan. Demand for health care services has increased by more than 5 percent over last year. The VA originally predicted growth of about 2 percent.
The $1.5 billion is for the budget year ending Sept. 30. Mr. Bush has asked for an additional $2 billion for next year on top of his February budget request.
In passing the Interior bill, lawmakers approved a significant cut to the budget for the Environmental Protection Agency, mostly from an EPA clean-water fund that gives grants to states.
The agency was also given instructions regarding upcoming rules on human tests used to consider permits for pesticides. Pregnant women, infants and children could not be intentionally dosed with pesticides when judging pesticide permit applications.
The underlying Interior measure also contains $10 million to subsidize a memorial to Martin Luther King Jr. on the National Mall on a 4-acre site next to the Franklin D. Roosevelt Memorial. The funds were sought by Sen. Robert Byrd, D-W.Va., and Senate Appropriations Committee Chairman Thad Cochran, R-Miss.
The Senate sent the $3.8 billion measure funding Congress' own budget to Mr. Bush on a 96-4 vote. Lawmakers approved what they hope will be the final $42 million payment for the much-criticized Capitol visitors center project, which has ballooned in cost to more than five times its original estimate.
The 580,000-square-foot addition has been more than a decade in the making and was supposed to cost just $95 million when first designed in 1995. Under current estimates, it will be $528 million.