Statistical data on the values of financial indicators in individual fields in the Czech Republic are provided by the Ministry of Industry and Trade. Updated values are issued quarterly. However, within the statistical samples, there are on average 34 companies focusing on construction. Moreover, no document specifies the size of the companies. Although the scientific literature provides basic financial rules, this research has confirmed that companies of different sizes show different values of financial indicators. For this reason, one of the aims of the research described in the article was to verify the hypothesis that companies of different sizes have different approaches to financial management and the other aims was to focus on correlating data on key financial indicators of individual sizes of companies with statistics provided by the Ministry of Industry and Trade. Basic methods of financial analysis (vertical analysis), selected ratios and basic statistical methods, which include correlation analysis, were used. The analysis was performed on 30 samples of construction companies, which were divided by size into small, medium and large. The outputs of the research will be further used for the follow-up research.