The response to four levels of K fertilizer (0, 100, 200 and 300 kg K20ha) by maize (Zea mays var. Metro) on two known K-deficient soils of different texture (Munchong and Serdang) formerly under rubber, was studied in a pot experiment for three months, in relation to various K extraction methods. A significant increase in the dry matter yield of maize was found in the sandier Serdang soil, with 100 kg K2 0/ha; higher levels did not give increased yields. At 100 kg K2 0/ha level, dry matter yield response was also detected for clayey Munchong soil, but the total K uptake was significantly higher at 200 kg K2 0/ha in this soil than in Serdang soil. Extractable K by CH3COOH gave the highest significant correlation with the stem portion in Serdang soil (r = 0.921) and with the leaf in Munchong soil (r = 0.819).