Ranbaxy's boss recently sold a chunk of the company to a Japanese rival
The United States Food and Drug Administration (FDA) says it has banned the import of more than 30 generic drugs made by Indian drug firm Ranbaxy.
The FDA said the decision was made after it found manufacturing quality problems at two of Ranbaxy's factories in India.
The import ban affects some popular generic versions of antibiotics and cholesterol medicines.
Ranbaxy says it is "disappointed" with the decision of US drug authorities.
The FDA said the move would not create any shortages of drugs in the United States, which could be obtained from other sources.
In July, US prosecutors had alleged that Ranbaxy, India's largest pharmaceutical company, deliberately lied about the quality of its low-cost drugs, including those for HIV.
The US Department of Justice wanted the firm to hand over key documents relating to drug testing procedures.
Ranbaxy said it was "very disappointed" with the FDA action.
"The company has responded to each concern FDA has raised during the past two years and had thought progress was being made," the firm said in a statement issued on Wednesday.
The firm was paid millions of dollars by the US government to provide low-cost HIV drugs for President Bush's emergency plan for AIDS relief, which was set up to help AIDS patients in 120 countries around the globe.
Defending the reliability of its drugs, Ranbaxy had said the US Food and Drugs Administration had tested over 200 random samples of its products and found them "complying with all the specifications".
In June the Japanese pharmaceutical company Daiichi Sankyo agreed to pay more than $4bn (£2bn) for a controlling stake in the firm.
The US government has been investigating Ranbaxy since February 2006 when the FDA issued a warning letter over what it said were manufacturing violations found at a Ranbaxy factory in India.
Since then Ranbaxy has been trying to resolve the issue with US regulators.
Last year, US officials seized documents from Ranbaxy's US headquarters in New Jersey.
In July, Justice Department prosecutors alleged that the company had systematically lied about the makeup of its generic drugs, which include a cheaper version of US drug maker Merck's cholesterol pill Zocor.
Ranbaxy has denied any wrongdoing, saying the allegations were baseless.
The FDA will only approve cheaper generic drugs if they can be shown to be equivalent to the original drug.
US investigators had also alleged that Ranbaxy has used unapproved ingredients in its drugs.