Two field experiments concerning sweet potato crop were carried out during the two successive summer seasons of 2009 and 2010 at a newly reclaimed area, at El-Nubariya city south of Alexandria governorate, Egypt. The experiments were designed to study the efficiency of the film-forming antitranspirant (Folicote) concentrations; i.e., 0, 5, 10, 15% (v/v) on optimization irrigation water in the low-water areas. Four irrigation quantities were applied; 1800 m3/fed., 2080 m3/fed., 2360 m3/fed. and 2640 m3/fed. (common rate) to investigate the effects of water deficiency on some important economic traits on sweet potato crop. The studied vegetative characters were positively affected with increasing Folicote concentration from zero up to 15 %. The total tuber root yield per fed. trait was gradually increased with increasing Folicote concentrations from zero up to 15 %. The decreasing of irrigation quantity from 2640 m3/fed. down to 1800 m3/fed. led to negatively effects on sweet potato yield and the economical studied characters. It could be concluded from this study that 280 m3 water per feddan could be saved when sweet potato plants foliar sprayed with Folicote at the rate of 15 % and at the same time obtaining high yield compared with the common irrigation water quantity (2640 m3/fed.). Folicote applications resulted in significant increases in the water-use efficiency over the control treatment. The increases in water-use efficiency were about 36.05% and 18.40% over the control treatment (zero Folicote) when 15 % Folicote was sprayed on the sweet potato foliage during the two seasons of the study, respectively.