This research was conducted using normative juridical research methods and literature studies regarding the Arisan Online Phenomenon in Indonesia. There are many cases of fraud using the Arisan Online mode which are carried out on various social media such as WhatsApp, Facebook and Instagram. This is due to increasingly sophisticated technological developments that make it easier for any transactions via the internetto be easy. However, apart from the positive impacts, there ae also negative impacts through this development. One of them is Online-based Arisan Which is prone to Fraud. In this study, it describe how legal protection is for victims who experience losses as a result of online-based arisan in terms of article 1243 of the civil code and how to enforce the law against owners of unlicensed inline arisan. Arisan online has the force of law as in article 1320 of the civil code because it is includein the agreement. Arisan online involves electronic media so that ther is a connection wth the ITE Law. Arisan is an agreement so that it binds the parties who make the agreement. Because binding one another ultimately creates Right and Obligations and if these right and obligation are not fulfilled it will result in default or unlawful acts. This default can lead to legal consequences, namely compensations, cancellation of the agreement, transfer of risk and payment before the judge.