The construction of concrete structures is a complex process that includes design, construction and control of concrete conformity. This paper describes the applicable legal obligations, rules and documentation during the design and construction of concrete structures. Furthermore, the participants in the concrete construction process, their obligations and requirements that they must take care of are listed. Special emphasis in the work is placed on the quality control of certified and noncertified concrete production and the conformity of concrete with the conditions of the construction Project, in accordance with the requirements of the HRN EN 206 standard: Concrete - Specification, performance, production and conformity. The conformity of the superbly designed concrete by the concrete company as an expert was checked at the construction site DC403 - Škurinje, as well as on its own concrete recipe made in laboratory conditions. The confirmation of conformity was carried out according to Croatian normative documents based on European norms. The conformity of the concrete delivered to the site was fully confirmed - while the conformity of the own concrete mix with the specified requirements of the Project was not confirmed in the majority of cases. For the continuous production of only one type of concrete, time was invested and several failures were experienced, which required refinement and repetition of the recipe in order to achieve the required properties. Just such a process of trial and error is inevitable to achieve satisfactory results.