Family businesses are found in all segments of the economy, from small to large size. Family-owned businesses may be the oldest form of business organization in which plays a major role in the economic growth and development of countries and in Medan city itself. Family businesses have the potential to outperform any other form of business organization through their inherent synergies between capital and management. In family business, the existence of family participation in the company can strengthen the family company. The family involvement in business is crucial as they are the one who owned the business and knows the exact purpose of the business clearly than from other people.The purpose of this research is to analyze the involvement of family members towards company’s success at PT. Industri Plywood Tjipta Rimba Djaja. The primary data is collected by using a quantitative method by surveying employees through a questionnaire. The results of data quality testing show that coefficient of correlation is 0.511, which shows moderate correlation between Variable X (the involvement of family members) and Variable Y (company’s success), and determination test shows that 26.1% of the company’s success is affected by the involvement of family members in the business. Through the research, it is concluded that family involvement in the business has a positive relationship with the company’s success of PT. Industri Plywood Tjipta Rimba Djaja.