The House voted yesterday to greatly expand the number of immigrants allowed into the country each year, giving increased priority to highly skilled workers and natives of some European countries who have been virtually shut out since current immigration laws were established 25 years ago.

"Today's House action will preserve our heritage of attracting the best and the brightest from all over the world who come to America to build a better life," said Rep. Bruce A. Morrison (D-Conn.), who sponsored the bill.

The legislation, approved 231 to 192, would increase by nearly a quarter of a million the number of immigrants allowed to enter the country annually, setting an upper limit of 775,000. The Senate passed its own version of immigration reform last year that would set a lower cap at 630,000 and place less emphasis on expanding the diversity of the immigrant pool. The current limit is 540,000.

The legislation passed yesterday faces a number of obstacles as it heads into a conference committee, including a crowded congressional agenda in the last weeks before adjournment and opponents who claim the changes will take jobs away from Americans and bring too many immigrants into the country.

While the Bush administration said it would support the Senate version, some agencies have recommended a veto of the House bill.

But White House spokeswoman Alixe Glen said a veto was not certain if some of the administration's concerns about the House version of the bill are ironed out in conference.

If a new law is enacted, it would be the first time since 1965 that the nation has revised its laws affecting legal immigration and only the third time in history the system has been reformed.

In 1986, Congress overhauled the laws affecting illegal immigration, granting amnesty to 1.7 million undocumented aliens.

Reflected in the House bill are two competing interests -- that the nation continue to promote family unification and that it attract highly skilled workers to industries suffering from labor shortages.

There was also strong pressure to allow into the country more immigrants from countries in Europe -- especially Ireland -- and Africa.

The current law, enacted in 1965, abolished country quotas and granted 95 percent of visas to immigrants who already had family members here. As a result, it worked in favor of those countries with recent immigrants, particularly Asia and Latin American nations.

It worked against countries with few recent immigrants, particularly the European countries that had sent immigrants here before 1965.

The House bill would triple the number of "employment based" visas -- from 54,000 to 188,000 annually -- that allow entry to workers who could fill jobs for which employers claim there are no qualified Americans.

"The main driving force of this law has been a recognition by economists and business leaders that, given the labor situation, there's a growing need for more skilled labor and more skilled immigrants," said Stephen Moore, a research fellow at the Alexis de Tocqueville Institution in Palo Alto, Calif.

The House bill would increase from 436,000 to 520,000 the number of "family-based" immigrants annually. These are people with close relatives that are citizens or permanent residents of this country.

To increase the number of immigrants from European and African nations, the bill would create a new "ethnic diversity" category of 55,000 visas annually to countries that have had few immigrants since 1965.

Opposition to the bill centers on the argument that given the nation's unemployment rate, there is not a shortage of skilled labor, and that an influx of immigrants would deny good jobs to Americans.

"The idea that we have a labor shortage in this country is ridiculous," said Ira Mehlman, research director of the Federation for American Immigration Reform.

Rep. Lamar S. Smith (R-Tex.), whose amendment to reduce the total cap to 630,000 was defeated, said final passage of the legislation was in doubt, given opposition in the House and a possible Bush veto.

But congressional aides said they were optimistic an agreement could be reached and a bill passed before adjournment, expected Oct. 19.

The House bill would increase the number of immigrants allowed into the country from 540,000 to 775,000. The Senate bill would raise the number to 630,000.

The House bill would increase family-based immigration from 436,000 to 520,000. The Senate bill would raise the number to 480,000.

The House bill would increase employment-based immigration from 54,000 to 188,000. The Senate bill would raise the number to 150,000.

The House bill would create a new category of 55,000 ethnic diversity visas, designed to open up immigration from countries -- primarily European and African -- virtually shut out under current law. There is no comparable provision in the Senate bill, but a "point system" for 54,000 visas included in the Senate's employment-based category would take diversity into consideration.