The article deals with the problem of assessing agricultural land used for the placement of objects (buildings, structures, structures) used for the production, storage and primary processing of agricultural products. The problem is that the owner who has provided (sold) a land plot for an object can rightly claim a part of the future profit that arises from the synergistic effect of adding two assets - land and improvements. The work purpose is to formulate a methodology for assessing agricultural land located under buildings, taking into account the synergistic effect and their properties. In the course of the study, two approaches were considered for determining the entrepreneur's profit for the evaluated objects: first, on the basis of the economic results of the agricultural enterprises activities; secondly, on the basis of the invested funds alternative investment possibility. It was revealed that the owner of the land that will be built up, as a co-investor of the project, has the right to add to the value of the land in the amount of the rate of return on invested capital - 26.28%. The market (in this case, the cadastral) value of the surrounding land can be obtained from the results of the assessment of lands of the first type of use (arable land, pastures, hayfields).