Among the important issues in Islamic Law are unauthorized contracts. Considering the jurisprudence books both in Shia and Sunni theology; it is revealed that there are many detailed discussions and branches studied by Islamic jurists. Of these, the most fundamental issue is to identify the descriptive effect of the aforesaid contracts. Other discussions about unauthorized contracts are dependent on accepting the validity of unauthorized contracts. This article specifically seeks to find the answer to what the descriptive effect of the unauthorized contracts is in Shia and Sunni jurisprudence? This research shows that there is no consensus nor among Shia or Sunni jurists and generally some think the unauthorized contracts are valid and others disagree. Referring to the evidence of verdicts and critiques and evaluations of unauthorized contracts validness, it is understood that the reasons of this group despite of their great fame, are not able to establish the validity of unauthorized contracts and the opposite view weighs more.