What would be the acceptable criteria for the authorship of research papers? In order to study this question, we analyze the relevant part of the results from the on-line survey that we performed to investigate the general attitudes of biomedical researchers as regards a number of issues of research ethics. The survey targeted the members of the Korean Society for Molecular and Cellular Biology, and 659 members responded. We ask questions such as who should be included as author, who is generally de factoincluded as author, and what are the problems in the decision of authorship. The results show that there are significant difference between Principal Investigators and research students in their responses, and that researchers in general tend to think the authorship is actually given more generously than it should be. We also examine the authorship criteria suggested by the International Committee of Medical Journal Editors(ICMJE), and its trend of changes. Finally, we discuss a few major issues Korean researchers facing when they decide authorship.