The article considers the concept of law-based state as a basis for justice effectiveness analysis. The necessity of researching the concept of a law-based state prior to covering the judicial system as a characteristic of a law-based state is methodologically justified. It is emphasized that for the development of Ukrainian legal science it is extremely important to investigate how exactly the effectiveness of justice is related to the extent to which Ukraine corresponds to the ideals of the law-based state, especially in the conditions of modern transformations. It is noted that a law-based state is based on the rule of law, the separation of powers, human rights and freedoms protection, and the independence of the judiciary. The theoretical and practical aspects of a law-based state functioning are considered, in particular the role of constitutionalism and legal mechanisms of control. The article emphasizes the importance of justice as a central element of a law-based state, which ensures the protection of citizens’ rights and control over the actions of state authorities. It was noted that in the context of a law-based state formation the effectiveness of justice acts as an indicator allowing to assess how successfully the ideals of the rule of law and the protection of human rights are implemented. The main criteria for evaluating the effectiveness of justice are determined, namely the independence of judges, access to justice, and fairness of decisions. The connections between effective justice and the principles of the rule of law and its role in a democratic society are covered. It is indicated that in the conditions of reforming the judicial system in Ukraine, the issue of maintaining a balance between the independence of courts and their accountability to society has not only domestic political significance, but also directly affects the international image of Ukraine and the process of European integration. It is summarized that effective justice is one of the most important indicators of a law-based state development. It ensures the protection of the rights and freedoms of citizens, contributes to the stability of society and the development of democracy. In order to achieve effective justice, it is necessary to constantly work on the legislation improving, qualifications of judges extension, and judiciary independence ensuring.