Buying and selling is an agreement to exchange goods or money for goods between both parties willingly and mutually. A sale and purchase transaction is considered valid if it meets the pillars and conditions of the sale and purchase. However, society often engages in practices that contradict Islamic law. This is evident in the practice of buying and selling mixed fruits in crates at the Pasar Grosir Buah dan Sayur Ngronggo Kota Kediri. In this practice, fruits of different qualities are mixed together in crates, and the buyer is unaware of the overall quality of the fruits, resulting in a disadvantage for one party. This research aims to explain the practice of buying and selling mixed fruits in crates and clarify the factors that underlie this practice at the Pasar Grosir Buah dan Sayur Ngronggo Kota Kediri. This research is a field study that utilizes a qualitative and empirical approach. The data sources utilized include primary data and secondary data. The data collection methods used are observation, interviews, and documentation. The data obtained are analyzed through an examination of Islamic legal sociology, and systematic conclusions are drawn. The research results indicate that firstly, the practice of buying and selling mixed fruits in crates at the Pasar Grosir Buah dan Sayur Ngronggo Kota Kediri involves the mixing of fruit qualities by the crate sellers. Buyers can only see the fruits from the outside of the crates. The mixing of fruit qualities is not permissible under Islamic law and contains an element of gharar (uncertainty). The behavior of the sellers contradicts the principles of honesty and trustworthiness in Islamic transactions. Secondly, the factors that underlie the persistence of this practice, despite the prohibition of mixing fruit qualities in Islamic law due to the presence of gharar, are economic factors and convenience. Sellers seek to obtain profits by including rejected fruits of lower quality during the packaging process. Economic factors and convenience play a role in facilitating this practice. Additionally, buyers are enticed by the low prices to sell the fruits in retail or per kilo, and middlemen are also attracted to this practice. However, upon opening the crates, they still find rotten or defective fruits inside. Based on M. Atho Mudzhar's theory, it can be concluded that the level of adherence to Islamic law by sellers and buyers is very low. They are aware that the mixing of fruit qualities in crates is prohibited in Islam, yet they continue to engage in buying and selling activities that clearly involve elements of gharar (uncertainty).