Abstract : This study examines the justice of profit distribution in Islamic financial institutions by analyzing the performance of the weights system. It intends to assess whether the weights system effectively achieves justice in calculating and distributing profits between the institution and its clients in these contracts. The research questions include whether reliance on weights as a fair system in the distribution of profit in mudharaba-based deposit accounts between Islamic financial institutions and their customers provides justice for both parties of the contract. The study also examines the notion of justice in Islam and its quantification in the banking sector. This study focuses exclusively on mudharaba-based accounts inside Islamic financial institutions while excluding non-mudharaba-based accounts. The theoretical framework has three components: mudharaba in Islam and the financial system, justice and consent between parties, and investment pools and weights system in Islamic financial organizations. The research employed qualitative methodologies, namely exploratory and analytical approaches, to collect insights into the weights system in Islamic financial institutions. The data was collected via interviews with specialists from various Islamic financial organizations. One of the key study findings is the presence of Justice while implementing the weights system, which is approved by Sharia supervisory boards in Islamic financial institutions and several fatwa committees, as well as AAOIFI sharia standards. Furthermore, the weights system must be detailed by the relevant organizations, such as Islamic financial institutions (IFIs) and regulatory bodies. The research suggests enhancing the openness and disclosure of the relevant weights in Islamic financial institutions, as well as providing a well-defined framework for the weights system that promotes fairness and guarantees the independence of Islamic financial institutions.