More than a quarter of people surveyed in Ebola-hit areas of the Democratic Republic of Congo told researchers they do not believe the disease exists.
Some 36 percent of respondents also believed that the disease had been fabricated to destabilise the country.
The authors of the study, published in the Lancet, said this mistrust was a factor in prolonging the epidemic.
According to the Health Ministry the current outbreak started in August last year and more than 600 people have died.
More than a thousand people have contracted the virus during the current outbreak, which is the second-largest ever recorded.