International real estate transactions, especially in countries with different legal systems, are characterised by the fact that each transaction is unique in its complexity, confidentiality, different risk factors, and the limited availability of information regarding the real estate. The Due Diligence (DD) process is an instrument that can help avoid or at least reduce risks and assist in making important decisions regarding real estate transactions. The term “Due Diligence” has a number of different meanings. The aim of this paper is to determine the etymology of this term and to identify its most common contemporary meaning. Each DD process is to be recognised as a project requiring management because of the potentially high number of individuals that could be involved.