The purpose of specialized medical journals is to accurately disseminate the results of new research. The peer-review process is crucial for journals to be able to fulfill this purpose. Although the peer-review determines whether scientific papers are accepted or rejected for publication, for many authors is a not well known process in its entirety. Many journals have focused on educating their audience about how and what is assessed during peer-review, nevertheless, the rate of manuscripts rejected because of easily-avoidable causes related to this, remains high. In this paper, we describe the process that specialized journals use to assess original medical manuscripts and list the main causes of paper rejection. Practicing physicians and medical students who wish to report their research results stand to benefit if they can identify and early avoid on the issues that most often arise during the peer-review process.