Corporate social responsibility has become a key aspect of modern business, as it encompasses the activities that companies carry out in order to achieve positive effects on society, the environment and the economy. Family businesses, which make up a significant part of the Croatian economy, often integrate CSR into their business strategies based on long-term family values and traditions. This final paper explored the activities of corporate social responsibility in selected Croatian family businesses of various sizes - micro, small, medium and large family businesses. The analysis was based on secondary data collected from various sources, including company websites and relevant publications. The research methodology includes categorizing companies by size and analyzing their CSR activities, challenges, and impact on business success and reputation. The results of the research have shown that the size of the company significantly influences the approach and implementation of CSR. Micro enterprises focus on local communities and the environment through activities such as recycling and waste reduction. Small businesses are implementing more formal CSR programs, including energy efficiency and sustainable resource management. Medium-sized enterprises implement advanced technologies and participate in international sustainability initiatives. Large companies have developed CSR strategies that include the entire value chain and report on their activities through annual reports. Examples from practice have shown how family businesses successfully integrate CSR into their business strategies, such as environmentally sustainable production, support to local communities and innovation. Based on the results of the research, the paper offers recommendations for improving CSR in family businesses of various sizes, including the development of strategic plans, stakeholder engagement, and systems for monitoring and reporting on impacts.