Presented contribution deals with the problem of impacts of brownfields on prices of surrounding real estates, thus, the aim of the paper is to investigate how and why unused sites and buildings reduce prices of real estates located in the proximity of brownfields. This assumption has been surveyed and confirmed by primary research that was done in the area of three municipalities (Karvina, Orlova and Detmarovice) in the Moravian-Silesian Region (the Czech Republic). Respondents of the survey also expressed their opinions and attitudes about factors and characteristics of brownfields that are of key importance from the point of view their negative impact on the prices of real estates. Primary research has been conducted by means of the questionnaire survey in the second half of 2016 and beginning of 2017. The results from questionnaire survey are also comparing to each other with the aim to find out the differences between respondent´s answers in particular municipalities.