The article is devoted to research of problems and substantiation of definition of zones of cultivation of the basic crops in Ukraine. The basic basis for determining the areas of cultivation of basic agricultural crops is recommended natural-agricultural zoning (the allocation of zones, provinces, districts, natural-agricultural areas), which is a consequence of agri-environmental heterogeneity of the territories of Ukraine. But the scheme of natural-agricultural zoning can be considered only as a frame when it comes to thematic in this case agri-environmental differences of the territory of Ukraine. An attempt to understand them and to distinguish them is necessary in the classification of arable land for the suitability of soils for the cultivation of basic crops. If we consider at least briefly the methodological sequence of determining suitability, the first question arises about the allocation of areas of cultivation of these crops, namely: winter wheat, winter rye, barley, oats, corn for grain, sugar beet, sunflower, potatoes, flax.For this purpose, according to published data, it is necessary to study, analyze the requirements of individual crops for heat, moisture, light at different phases of development, determine the quantitative need of each factor during the critical periods of plant growth and development, and accordingly, supporting tables for these crops should be drawn up. On the basis of these data, they form a complex characteristic of arable land of Ukraine in relation to the agro-ecological requirements of these crops. The characteristics include, firstly, the total area of the crop cultivation area in Ukraine and the affiliation of certain parts of it to taxa (units) of natural agricultural areas; secondly, each individual zoning taxon has areas that are subject to the suitability of arable land of a particular crop and a score of that area for yield. The area of the first, second and third subclasses of suitability for the area of all cereals, the first and the second — for other named crops, that is, the area on which the cultivation of crops is not accompanied by radical amelioration measures is related to the suitability of the area. This is information that allows us to identify areas with a relative environmental optimum for each crop. It is very important that having suitable acreage and yield estimation, it is possible to determine the production volumes of individual crops under conditions close to the ecological optimum, which is also one of the decisive factors in creating real prerequisites for environmentally friendly land use.