This thesis on statistical analysis of defects in construction practice deals with the assessment of defects which are monitored within the system of construction and technical prevention in the period from 2010 to 2013. We cannot consider as defects such matters arising from non-compliance with the contractual relationship between the sponsor and implementer of the building work, and that this does not contradict the building Act. This thesis aims to determine the defects in construction practice and the right tools, statistical analysis, and quality control methods to assess the state and evolution of defects, as well as to find links and dependence of defects on defined factors. The methodological part of the thesis is based on an exploratory statistical analysis of qualitative data, Pareto analysis, and also statistical testing of the hypothesis of independence using the chi-square test of independence in the pivot table. The strength of any relationship is tested under Cramér V. The output of the thesis is a list of the most frequently occurring defects in construction practice, a description of the defects, and their evaluation in terms of occurrence in time, within a defined territory, and the occurrence of a specific building construction.