Double publication can be started with double (or multiple) submission. Double submission can be defined as "the submission of a paper to a journal after that is under concurrent review by another publication". Authors should only submit original work that has neither appeared elsewhere for publication, nor which was under review for another refereed publication. Guidelines for authors of many journals contain prohibition of double submission. For example, in instructions for author of Diabetes Care, we can find such a policy as follows. "Diabetes Care publishes only material that has not been published previously (either in print or electronically) and is not under consideration for publication elsewhere".

Recently we found a case of double submission. In the course of review, a reviewer of the Korean Journal of Family Medicine (KJFM) found that the manuscript was already published in a foreign Science Citation Index (SCI) journal. Double submission is also considered unethical because it may result in double publication. Double submission can take place for many reasons: the author may not know that double submission is unethical, may be a junior researcher, or may not want to delay publication. Whatever the reason, double submission is a form of publishing misconduct.

For the previous case, we will contact corresponding author, will state that submitted work has already been published elsewhere, and will ask for explanation about that. If the author gives a sufficient and reasonable explanation, we reject the submission without penalties. However, if the author does not respond, the explanation is unsatisfactory, or the author admits guilt, we will reject the submission with penalties, for example, sending a letter of warning, imposing a ban on submissions to KJFM for one or two years, or informing the author's superior about the misconduct.

Double submission remains one of the least well understood forms of publishing misconduct, and has significant negative impact on the research community. Establishing clear guidelines and training junior researchers sufficiently can help reduce the problem of double submission.