Agriculture officials were told to "begin the expropriation process," The Associated Press says.
The multinational has had operations in Venezuela for the last 13 years, producing parboiled rice.
Anti-US Chávez, who is popular in his home country for controlling prices of consumer goods, has implemented price controls on basic white rice.
"I warn you, this revolution means business," said Chavez, according to Reuters.
Cargill has said it is respectful of the decision, but hopes it can be resolved through talks. In addition to rice, Cargill has 2000 employees in Venezuela, and operations there in oilseed processing, grain and oilseeds trading, animal feed, salt, and financial and risk management.
It is not known whether these operations have been affected.
Over the weekend Chavez ordered troops to seize other rice-producing plants he accused of violating price controls.
Owner Polar has pledged to take legal action, according to the International Herald Tribune.