ABSTRACT A small size one-row prototype machine for digging potato was fabricated locally to be simple in design, low fabrication costs, ease to operate for digging, cleaning potato tubers in small holdings under sandy soil conditions. The practical experiments of this study were carried out to evaluate the performance of the machine under four forward speeds of 1.40,2.30,2.95 and 3.50 km/h , three blade rake angles of 10°,14°and 20° and three digging depths of 25,30 and 35 cm taking into consideration machine actual capacity, product losses, harvesting efficiency, cleaning efficiency, required energy and criterion cost of harvesting comparing with the manual method of harvesting(Hand hoe method).The obtained results revealed that the proper operating conditions for the prototype potato digger in small holdings are forward speed of 2.30 km/h , rake angle of 14° and digging depth of 30 cm to achieve actual field capacity of 0.23 fed/h and the lowest percentage of total losses including 2.90% for the damaged tubers and 1.20 % for the un-harvested tubers , high harvesting efficiency of 95.50 % and the highest cleaning efficiency of 95.32 % with minimum criterion costs of 381.32 LE/fed at required power of 16.42kW and specific energy requirement of 71.39 kW/h.fed, but for the manual digging, the results showed that the average labor field capacity is 0.026 fed/h, average harvesting efficiency is 82.51% and the average criterion cost is 1250.28 LE/fed. Hence, it can be concluded that the prototype digger is less for both losses and costs with high harvesting efficiency comparing with the manual method in small areas. Keywords: small holdings, prototype, rake angle, criterion cost, hand hoe