the potato crop is considered one of the important vegetable crops in Egypt, which occupies a prominent place among the green plants in the crop structure of Egypt, the average total cultivated potato crop during the period (2008 - 2012) about 355.58 thousand feddans represent about 5.5 % of the annual average total area cultivated vegetables in Egypt, which is estimated at 6412.3 thousand feddans during the same period, while the average total quantity of production of potatoes about 3.94 million tons represented about 11.9% of the average annual total production of Egyptian vegetables estimated at about 75.53 million tons in Egypt during the same period. The problem potatoes crop is consendered the most important of food vegetables crops for habitants in Egypt .but the production of this crop represents only 11.9 %from the totalof vegetables production in A .R .E , in addition to the damage proportion in this crop is estimated with about 12 %,that leads to reduce unclear in production which that lead to rising the production costs of potato crop .The research aims to study the current situation of production and cost for potato crop on the level of Gharbia Governorate, and studying the productive efficiency of the most important resources used in potato production, Also study the costs of production of this crop . The research results from the variance analysis of moral differences between the micanical labor of feddan used for potato to the first category and the second category insample of each: irrigation machine, mator spraying, tractor, harvest tractor, for potato crop in the first category, the condition of economic efficiency has been achieved on the level of the total resources as long as there is an increase in the output of the potato crop, but less than the rate of increase in resources, where the relationship of decreasing productivity. Either for each supplier separately, a condition of economic efficiency and increase the value of marginal product of wages prevailing in the market for each component of the seeds, and the element of irrigation, but still possible to increase the efficiency by increasing the elements of production until the equal value of marginal productive of component and with the its price in the market, also the condition of economic efficiency in the second category has been achieved on the level of the total resources, and on the level of each of the element. The research also explained that the optimal size of the farm in the first category of potatoes reached about 11.60 tons, thus, farm size represented about 78.9% of the optimal size of the farm, as shown in the search that size which maximizes the profit of the farm of potatoes in this category amounted to about 35.27 tons, since the average farm area is about 0.54 feddans, so theaverage production per feddan of potatoes in this category amounted to about 16.94 tons and the reseach showed that the optimal size of the farm in the second category of potatoes reached about 27.28 tons, thus, farm size represents about 93.95% of the optimum size of the farm, as shown in the search that size which maximizes the profit of the farm of potatoes in this category About 59.92 tons, since the average farm area is about 1.54 feddans, so the average production per feddan of potatoes in this category amounted to about 16.64 tons.