This research aims, in general, to study the estimation of production costs functions in the Nubaria area in the Buhaira governorate, as it reflects the relationship between total costs and actual production, from which it is possible to derive the most important economic indicators that reflect the extent to which agricultural production units achieve economic efficiency in their use of productive resources participating in the production process. As well as the extent to which these units achieve in maximizing profits for the agricultural product, the problem is summarized in the existence of a wide variation in the size of fruit farms in general and farms specialized in banana production in particular, as they are distributed between acres for small farms and more than one hundred acres for large farms, and the total production flexibility was estimated (EP) for the function by about 1.16, which means that an increase of these elements by 10% leads to an increase in the total production of bananas per acre by about 11.6%, and this shows that production takes place in the first stage of production, which is the stage of increasing the return to capacity, as the percentage of increase in the amount of total output per acre It is greater than the percentage increase in the quantity of production factors used, which means that the return to capacity will increase because the elasticity of production is greater than the correct one.