Phenolic acids are effective feeding deterrents and serve as precursors to more complex phenolic compounds, such as condensed tannins, that are associated with insect and disease resistance. Phenolic acids have been studied extensively in many plant species, but the role and concentrations of these compounds have not been characterized in cotton. This study was conducted to quantitate concentrations of some commonly occurring phenolic acids and to examine the relationship between these compounds and condensed tannins in six cotton genotypes that vary in spider mite resistance and in condensed tannin concentration.