Many government and funding bodies around the world have been advocating open access to research data, arguing that such open access can bring a significant degree of economic and social benefit. However, the question remains, do researchers themselves want to share their research data, and even if they do how far they are prepared to make this happen? In this paper we report on an international survey involving university researchers in three countries, viz. UK, France and Turkey. We found that researchers have a number of concerns for data sharing, and in general there is a lack of understanding of the requirements for making data publicly available and accessible. We note that significant training and advocacy will be required to make the vision of data sharing a reality.