In this literature review I have first provided an introduction in which I've clarified the meaning of focus on form issue and some debates about its advantages and disadvantages and the needed degree of focus on form in teaching structures in classroom. Then I have stated some features of focus on form and the ways that focus on form can contribute to the development of communicative ability which is the main purpose of second language learning. In the third section I have stated some linguists' ideas about focus on form which contains some agreement and disagreements between researchers. In the fourth section I have categorized some structure-based proposals by some linguists and consider their suggestions on activities and techniques. I have compared their viewpoints. This section is followed by different techniques of focus on form in instructions in the classroom settings and instructional activities. I also have listed some suggestions of researchers about different kinds of activities. In the fifth section I have examined the effectiveness of focus on form instruction within a variety of instructional circumstances as proposed by some researchers. They have done some practical researches in focus on form and I have listed their results in a kind of comparison form of their works. In the sixth part I have listed some limitations of focus on form mentioned by some researchers which can be considered in curriculum designing and the practical teaching. In the last part I have written the conclusion.