Hwang Woo-suk's research team "did not have any proof to show that cloned embryonic stem cells were ever created," an investigating panel at Seoul National University said in a report, disputing claims in Hwang's 2004 paper in the journal Science purporting that he cloned a human embryo and extracted stem cells from it.
The panel found that Hwang's claims last year to have created the world's first cloned dog, however, were genuine.
The university made the announcements as it released the final results into its investigation of Hwang's cloning research, which came into doubt late this year after accusations emerged that the research was fabricated.
Hwang, a professor of veterinary medicine, said after the university's interim report was released last month that he would resign from the school, but has yet to tender his resignation.
The university plans to determine any penalty after concluding the investigation.
South Korean prosecutors also are preparing their own investigation, which would include Hwang's allegation that other researchers in his lab maliciously switched some of his stem cells.
South Korean media have said Hwang, who received massive government funding for his research, may also face charges of misappropriation of funds.
Hwang has claimed that he has the technology to clone stem cells, and that he could reproduce his experiments.
Scientists say stem cells could be a potential source of replacement tissue, possibly offering hope for treating ailments such as Alzheimer's disease and diabetes.