She demanded that the Congress-led UPA government roll back the decision immediately, failing which her party would be forced to take some harsh decision.
"In a bid to benefit the foreign companies and to make the country a slave on the lines of East India Company, the Centre has decided to hand over the economy in the hands of companies like Walmart," Mayawati alleged while talking to the reporters.
"The state government is writing a letter to the Centre in this regard," she said.
Hitting out at Rahul Gandhi, the UP CM said that as the Congress 'yuvraj' was brought up and educated in foreign country, his mindset was that of a foreigner.
"Therefore, whenever he comes to UP he brings along his foreign friends on leisure trip and for entertainment take them to the huts of poor people to make mockery of their poverty," she alleged.
She further alleged that the decision on FDI was taken to benefit companies of these foreigners and to make them billionaires.
"With UP assembly elections nearing, Congress 'yuvraj' in a bid to benefit companies of his foreign friends is indulging into dramatics to bring his party in power," she alleged.
"The decision to allow FDI was taken by the cabinet despite opposition by a UPA ally," Mayawati said.
The decision was taken by the UPA government despite knowing the fact that after the entry of the multinational companies, the economy would "completely go in their hands", she said.
"The country would become an economic slave. The Congress led UPA government knows that after entry of such companies small shopkeepers and industries will close down and crores of workers will get unemployed," the UP Chief Minister alleged.
She said that in such a situation, condition of crores of farmers and poor people, who were already forced to commit suicide due to wrong policies of the Centre, would turn worse.
With the entry of these companies, farmers would be forced to sell their produce at a lower rate and they would bring cheaper products from countries like China, she said.
"Despite knowing the fact, the government took the decision because it cannot make Congress 'yuvraj' angry at any cost," she alleged.
She said the decision would impact workers, farmers, poor and middle class section as they would be forced to buy products at a higher cost.
"The decision will be a fatal one...to fulfil the wish of a person, the Centre has permitted foreign companies to enter the retail market," she alleged.
The CM alleged that their entry would contribute in raising inflation at a time when people were already facing tough times due to high prices.
Mayawati said that she is confident that people would not let the intentions of Congress get fulfilled.
"I want to assure the people that till the time I am the CM no foreign company will be allowed to make investment in retail market and do business in the state," she said.
"The party will strongly protest the move in Parliament and across the country," she said.
On a question whether BSP would withdraw support from UPA, Mayawati said the issue was still pending inParliament.