That is, the study of comparative law can not only refer to the comparative study of the laws but also the comparative study of case law, enforcement, legal institutions and legal custom. After being cited and considered the definition of comparative law of various national and foreign authors, we can say that comparative law is the discipline that is dedicated to the application of the comparative method to the study of law. 3. Guillermo Cabanellas comparative method approach is scientific procedure for research and teaching of the truth. That is, the methods that we refer to are the methods used in scientific research within the law. To carry out an investigation there are several methods to which is called research methods among which include the inductive, deductive, analysis and synthesis (which are the best known methods of investigation by researchers because they are considered as general research methods, ie that are not only used in the study of law, but also in other areas of knowledge), but there are other research methods specific to the right from which we can cite the historical method, the exegetical method, the systematic approach, the sociological method and there is also the comparative method is not very developed in our environment, and taking into account that this paper refers to comparative law we now turn to that method of investigation of law, that is, then we will refer to the method comparison. Guillermo Cabanellas For the comparative method in the study of law is that based on exposure differences between the various legal institutions, to assess their consistency or make their peculiarities.