. Gunadi, N. 2007. The Use of Potassium Sulphate as an Alternative Source of Potassium Fertilizer in Potato. An experiment to determine the effect of potassium sulphate as an alternative source of potassium fertilizer in potato was conducted at a farmer's field in Padaawas Village, Pangalengan Subdistrict (1,400 m asl), Bandung District, West Java, from March to June 2002. Randomized completely block design with 3 replications was used in the experiment. The treatments consisted of combination of rate and source of potassium fertilizer (potassium chloride and potassium sulphate) i.e. (1) 0 kg K2O, (2) 50 kg K2O (KCl), (3) 100 kg K2O (KCl), (4) 150 kg K2O (KCl), (5) 200 kg K2O (KCl), (6) 250 kg K2O (KCl), (7) 50 kg K2O (K2SO4), (8) 100 kg K2O (K2SO4), (9) 150 kg K2O (K2SO4), (10) 200 kg K2O (K2SO4) and (11) 250 kg K2O (K2SO4). The results indicated that although the use of potassium sulphate in potato with a rate of 250 kg K2O per ha increased some growth parameters and yield components of potato, but it could not be easily replaced by the use of potassium chloride, which is commonly used by the farmers. The use of potassium sulphate affect positively only on specific gravity, but not on sugar reduction and starch content. The results could be used as a recommendation to select the source of potassium in potato production.