An abstract is a self-contained, short, powerful statement that describes a larger body of work. It may be incorporated as part of a published paper, book, grant proposal, thesis, research report, or a conference paper. An abstract of a scientific paper will be published online independently, so it should make sense when it is read alone. An abstract of a hypothesis-testing paper consists of at least four key elements, as follows: (1) study question/hypothesis/aim, (2) experiments/material and methods, (3) results, and (4) response to the question/conclusion(s). The abstract usually begins with a background and may end in applications, recommendations, implications, or speculations. The abstract is one of the many features of a manuscript that competes for the readers’ attention; therefore, it should be informative, accurate, attractive, and concise. Since a huge amount of work must be compressed into a few sentences, writing an abstract may be a difficult task that needs professional skills. Here, we provide a practical guide to writing an abstract and selecting Keywords for a hypothesis-testing medical paper.