The point in construction is that the project is completed in shortest possible period of time and, of course with minimal additional costs. In this graduation thesis it`s described one of the major construction projects on the Slovenian coast, namely the construction of tanks for petroleum products. The graduation thesis analyzes the deviation of the vontractual schedule and contractual estimate fot the construction of reservoirs R21, R22 and R23. Changes in the project which led to the time lag between construction and unexpected costs was described in detail, as well as the breakdown of labor, because at the facility involving several subcontractors, which represented additional obstacle in work. The construction of tanks for petroleum products also included the construction of the other supporting facilitiey.