When a claim is initiated, the defendant generally puts up a defense to prevent being convicted. This defense can be procedural, substantive or in the form of a counterclaim. The position of substantive or procedural defense is to a large extent clear. However, the case of a counterclaim is a bit complicated. Using the library method, reviewing the books and opinions of experts and taking into consideration the judicial precedent, the present research seeks to answer the question as to in which cases substantive defense is not adequate and the defendant should initiate a counterclaim to defend his rights. It seems that in two cases, the defendant should avoid merely presenting his defense in the form of a substantive defense and file a counterclaim. The first case is when the defendant is seeking to diminish certain privileges belonging to the claimant. This privilege can be material or moral, but in any case, the moral privilege should not be too abstract and should have a reasonable value. The second case would be where a counterclaim may exert a material impact on the defense put up by the defendant A clear example of a such a case would be a defendant's attempt to prove the invalidity of the notarial deed relied on by the claimant. In all other cases, it is not necessary for the respondent to file a counterclaim, and in order to avoid delays in the proceedings, it is recommended that this legal institution not be resorted to.