This paper addresses the issue of self-plagiarism in scientific research. What does self-plagiarism mean, what is the legal framework and in what context does it differ from double publication, paraphrasing, and compilation of ideas, texts, or papers? Self-plagiarism involves publishing/ reusing all or part of the same content, copypaste from a text/texts, expressions, demonstrations, data, hypotheses, theories, results, or scientific methods extracted from written works, double publication, compilation, by the same author, regardless of the language of presentation/ publication, at a certain time interval without making it clear that it has been transmitted in the past and without referring to the original source(s). Selfplagiarism is also the use of close paraphrasing, without fully and correctly mentioning the original source of the text. Self-plagiarism is very clearly committed in a situation where an author, without citing the original source, partially or completely re-exploits his own work. This fact usually arises from the desire to multiply the list of works and implicitly the CV.