According to the analysts at Gartner, a whooping 85% of some of the world's top companies are using Open Source software.
And the remainder are planning on moving across within the next year.
The findings come after a survey of 274 end-user organisations across the Asia/Pacific, Europe and North American markets in May and June.
The companies involved in the research pointed to cost as the main reason for using Open Source software but also the fast times to market and the fact that they could avoid getting involved in complex procurement rules and procedures.
However, the survey also found that companies do not have formal policies towards the Open Source software they use, which could mean that they are infringing copyright without realising it.
Only 31% of the companies "had formal policies for evaluating and procuring open-source software (OSS)".
"Just because something is free doesn't mean that it has no cost", said Gartner research director Laurie Wurster in a statement.
"Companies must have a policy for procuring OSS, deciding which applications will be supported by OSS, and identifying the intellectual property risk or supportability risk associated with using OSS. Once a policy is in place, then there must be a governance process to enforce it."
Wurster added that change will come but it could be "a slow process".