In a symbolic move, the leader wore the presidential sash draped from his left shoulder instead of the traditional right, while swearing by Jesus Christ, calling him "the greatest socialist in history."
When Chavez won re-election with 63 percent of the vote in December, he told the thousands cheering below the balcony of the Caracas presidential palace: "Today a new era has started, with the expansion of the [socialist] revolution."
In an effort to help bring about that revolution, Chavez has sought to strengthen his power by planning not to renew the license of a private opposition TV channel, RCTV, and announcing intentions to assume control of private companies currently held by foreign investors.
Chavez recommended Wednesday that the state take control of natural gas projects. Earlier in the week, he announced plans to nationalize currently privately held companies in the telecommunications and electricity industries.
Investors seemed concerned by Chavez's words and rushed to sell shares of companies that could potentially be affected by nationalization plans. The state currency, the bolivar, fell by as much as 20 percent in black market trading after Chavez's statements.
American corporations such as Verizon Communications presently hold large shares in the CANTV, the country's largest telecommunications company, according to the New York Times. Arlington, Va.,-based AES Corp. controls Electridad de Caracas, its largest publicly traded electricity company, the Times said.
It is unclear how nationalization plans would be implemented -- if the government would compensate foreign investors for their shares or if they would be merely expropriated from their holdings.
The United States has warned that Chavez is making a mistake by nationalizing companies, while Chavez has expressed an interest in further expanding the government's control, saying that four multibillion-dollar oil projects in the Orinoco River basin should become "state property."
The Venezuela government already has stakes in these ventures, along with oil powerhouses such as Exxon Mobil, Chevron and BP.
Chavez also announced plans to seek a "revolutionary enabling law" from Congress that would allow him to approve bills by decree and strip the central bank of its autonomy.
Although Chavez's critics seem wary of his measures, the Associated Press reported that the president remains popular among the country's predominantly poor population.
After his inauguration ceremony, Chavez flew to Nicaragua for the inauguration of '80s leftist revolutionary Daniel Ortega, who upon his recent election has taken a more moderate policy stance while also cultivating ties with leftists Chavez and Castro.