Technology transfer is the process of commercializing technology and taking it from the laboratory to the marketplace. At some stage in the technology transfer process, a due diligence will be undertaken. A due diligence is an enquiry into the technology and, in particular, its ownership. Research organizations including hospitals, universities, and blood banks need to own the intellectual property that they seek to commercialize. They own the intellectual property created by their staff in the course of employment. But volunteers, students, and collaborators, not being members of staff, will own the intellectual property that they create. This gives rise to due diligence and ownership defects, when intellectual property may in fact be owned by someone other than the research organization that seeks to commercialize it. Joint ownership can sometimes prevent commercialization. An assignment of intellectual property from a volunteer or student may sometimes be required. Such an assignment, if it inadequately deals with all relevant issues, may be void pursuant to laws throughout the world. A void deed of assignment may expose the research organization to legal liabilities. The categories of technology transfer traps to be explored are (1) ownership issues arising from the participation of students and volunteers in research, (2) ownership issues arising from collaborative research relationships, (3) ownership issues arising from the participation in research of visitors from another research organization, and (4) ownership issues arising from inventions made by employees. Each of these is considered in the context of the legal and regulatory framework in Australia, Canada, the United States of America, and the United Kingdom.