This chapter aims to provide an instructional review about how to write effective introduction sections for original medical research articles. First, the basic function and aims of the introduction section are discussed. The introduction has the most important social role in the text as it should act as a bridge for the reader to the more technical parts of the document. It should thus be written with the reader kept carefully in mind, and should be able to interest them and convince them of the study’s significance. Next, the major functions of a successful introduction are reviewed including the general background and motivation, the academic background and literature gap, the research problem statement, the methodology and the social impact. Using examples, these functions are analyzed according to the common English language features associated with them such as verb tense, noun types, common words and phrases etc. Some recurring errors made by non-native English writers relating to these language features are also identified. After this, ways to ensure that the separate introduction functions are crafted into a unified section are outlined. A general structure beginning from the broadest statement and narrowing to the most specific is suggested. Placing content-similar functions together, and binding them with cohesive techniques provides further connectedness within and between paragraphs and increases the readability of the text. Finally, a sample introduction and related exercises are given, so the reader can apply the concepts covered in this chapter.