Collective agreements in Croatian labor law represent a key mechanism for regulating labor relations between trade unions and employers. They ensure the protection and improvement of workers' rights, working conditions and social security. This paper will explain what the main subject of collective agreements is and how they contribute to better conditions for workers. Collective agreements regulate issues such as wages, working hours, vacations, as well as dispute resolution procedures. Collective agreements provide the basis for maintaining and balancing economic efficiency and social justice in the Republic of Croatia. It is important to emphasize that collective agreements are in accordance with national legislation and international human rights standards. Collective agreements provide stability and predictability to labor relations, which contributes to increasing productivity and competitiveness on the labor market and strengthening social cohesion and stability, which is key to the sustainable development and prosperity of the Republic of Croatia. Also, collective agreements can be an instrument for the improvement of gender equality, protection of persons with disabilities and minority groups in the workplace. Violation of rights related to racial, gender, national equality and other rights represents a violation of the fundamental values of the Constitution of the Republic of Croatia. The process of concluding collective agreements involves negotiations between trade unions and employers, which are often conducted in the spirit of social dialogue. These contracts regulate issues related to salaries, working hours and vacations, as well as procedures in case of disputes. In conclusion, collective agreements can provide stability and predictability to both workers and employers, which is essential for maintaining peaceful and harmonious labor relations. In times of challenges in the modern world of work such as digitalisation, globalization and changes in the organization of work, collective agreements can serve as a platform for the advancement of workers' rights in accordance with the changes. Also, collective agreements contribute to strengthening the social protection of workers through systems such as health insurance, pension system and social system.