Am inadequate potassium fertilization for the cotton crop may limit, eventually, the effect of liming in the correction of the acidity of certain soils, due to the unbalance of bases. With the purpose of clearing up this problem, a field experiment with lime and potassium applications was conducted on a Dystrophic Dusky Red Latosol. During five following years, a linear effect of dolomitic limestone (2, 4 and 6t/ha) upon cotton yield was noted, in the presence of adequate potassium fertilization; without potassium, liming effect was quadratic. At the highest liming, the level of soil pH increased from 5.1 to 5.8-6.0 and soil calcium plus magnesium content from 1.1 to 3.0-3.2meq/100cm³ soil. Cotton yield was highly correlated with pH as well as with soil Ca2+ + Mg2+ content. Ca and Mg concentrations in the leaf blade increased with liming, while those of K and Mm decreased. The effect of potassium fertilization (50, 100 and 150kg/ha of K2O) on cotton yield was quadratic and maximum at the highest liming level. It was observed that leaf Ca and Mg concentrations decreased with fertilization, while leaf K, Mm and Cl concentrations increased. Cotton yield was significantly correlated with leaf Cl concentration. It seems possible that, at high potassium chloride levels, chlorine toxicity may occur in the plants.