Illocutionary acts are the most important and pivotal acts in the theory of speech acts. Any attempt to develop a taxonomy must take into account John Austin's classification of illocutionary acts into five basic categories of verdictive, expositive, exercitive, behabitive, and commissive. But for John Searle, Austin's taxonomy is not the classification of illocutionary acts, but the classifications of English illocutionary verbs. Thus Searle lists problems in Austin's classification, including: the existence of persistent confusion between the verbs and the acts, the existence of a great deal of overlap between categories, the existence of great heterogeneity within the categories, and so on. According to John Searle, it is better to consider the five categories of assertive, directive, commissive, expressive and declaration as types of illocutionary acts. In his taxonomy of illocutionary acts, Searle also offers twelve different criteria and aspects of taxonomy, from which he chooses illocutionary point as the basis of his taxonomy and direction of fit and sincerity condition are corollaries it. But firstly, there is no complete taxonomy of speech acts, as Searle did, and basically cannot exist, and secondly, in Searle taxonomy, there is no precise explanation of the illocutionary point and corollaries of it. Thus, the main purpose of this paper is to critically examine Austin and Searle Taxonomies of illocutionary acts.