President Hugo Chavez said the firms' workers would be given help to set up co-operatives and re-start production for the benefit of the community.
He said the move was needed to fight poverty and end Venezuela's dependence on "the perverse model of capitalism".
Some business leaders fear it may lead to a wider attack on private property.
'Perfectly productive'
Speaking on his weekly television programme, Mr Chavez said the measures were necessary.
Either capitalism, which is the road to hell, or socialism, for those who want to build the kingdom of God here on Earth ………….***
CARACAS - Venezuelans' support for Fidel Castro's model of government and the installation of socialism here has been growing, two recent polls show, although a majority remains critical of the Cuban system.
The polls suggest that President Hugo Chávez, Castro's closest ally, is succeeding in shifting public opinion toward the left as he pushes his ''revolution'' among a population that historically identified more with the values of Miami than Havana.
Chávez, whose own approval rates are running at over 70 percent, makes frequent pro-Cuba speeches, and more than 20,000 Cuban medical personnel and sports instructors work in poor neighborhoods here.
A poll released last weekend by the Caracas-based Datanálisis company showed 11.6 percent approved using Castro's Cuba as a model for Venezuela, while 63.2 percent said they were opposed.
The percentage of pro-Cuban sentiment represented a significant increase. In July 2002, in response to the same question, only 3 percent expressed support and more than 91 percent were opposed. As recently as this January, the support was under 6 percent.
Another nationwide poll, carried out by Seijas & Asociados in late May and early June, showed that about 48 percent of respondents preferred a socialist over a capitalist system, with less than 26 percent preferring the latter.
After years of denying that his ''Bolivarian revolution'' -- named after independence hero Simón Bolívar -- was socialist, Chávez now openly calls himself a socialist and attacks what he calls the ''perversions'' of capitalism.
Datanálisis director Luis Vicente León warned, however, that the various poll results must be analyzed ''with tweezers'' and do not necessarily mean that Venezuelans want a Cuban-styled system in their country.
Venezuelans, León said, associate the Cuban system not with socialism but with communism, which the majority abhors. ''There remains a very high level of rejection of extreme models such as communism,'' he said.
''Chávez has not succeeded with his discourse in diminishing people's association of capitalism with well-being and development,'' León told The Herald. ``Nor has the opposition succeeded in demonizing socialism by reference to Chávez's relationship with Fidel.''
Venezuela and Cuba recently agreed to increase by the end of the year the number of Cuban medical personnel here to 30,000. The Information Ministry has reported that more than 9,000 Venezuelans have been treated in Cuba for everything from cataracts to heart disease. ………………………..***