Controlling in family versus non-family businesses (Diploma thesis). Controlling is an effective tool to actively manage the future of the company. This diploma thesis aims to map the state of use of controlling and its tools in family businesses in comparison to non-family businesses. In the first, theoretical part, we described the concepts of controlling, controller, controlling tools, family businesses, and family business. In the second part of the thesis, we focused on mapping the use of controlling and its tools in the practice of Slovak family and non-family businesses. We concluded that, in general, there is no significant difference in the use of controlling, the differences arose only for individual instruments. We see differences in strategic controlling in the tools: revenue and cost plan, calculation of planned costs, planned balance sheet, value analysis, and make or buy decisions, used more by family businesses. Non-family businesses use the following tools more often: profit and loss statement, calculation of short-term VH, ABC analysis, cash flow plan, critical point analysis. There were no significant differences in operational controlling as family businesses make more use of all operational controlling tools compared to non-family businesses. However, non-family businesses use these tools to a lesser extent. In financial controlling, there were differences in the following instruments: financial control, profitability indicator, liquidity, activity, indebtedness, EVA indicator, and quick test, these instruments are more used by family businesses. Non-family businesses use tools such as working capital calculation, cash flow, creditworthiness index. The differences in investment controlling are not so significant, as even in this case, family businesses make more use of all these tools than non-family businesses. In cost controlling, we can say that even in this case there were no significant differences in use, but all instruments are used more by family businesses. The result of the work is the identification of differences in the use of controlling tools in family businesses compared to non-family ones. These findings are beneficial for theory, science, and practice.