Participation of the parietal and frontal cortical areas in pattern discrimination learning was studied in cats. Extirpation of the parietal cortex (fields 5 or 7) produced a deficit of visual discrimination of simultaneously presented patterns, but the animals were able to relearn the task. Postoperative learning of simultaneous discrimination was abolished, although successive discrimination of the same stimuli was still possible. The parietal associative areas probably participate in the organization of spatially and visually controlled movements. The frontal lobe ablation eliminated pattern but not brightness discrimination learning. The lesion of the frontal lobe is apparently connected with the oculomotor mechanism of pattern discrimination.