Rats were trained using operant conditioning to discriminate either 0.9% NaCl from 0.1% saccharin or 0.75% NaCl from 1% sucrose and were tested on a series of seven successive discrimination reversal problems. Most animals made many more errors on the first reversal than on original learning (negative transfer) and none demonstrated acquisition of a reversal learning set. These results, together with those of prior studies in this laboratory, indicate that on reversal learning tasks the performance of rats trained with taste cues is inferior to those trained with odors and is quantitatively and qualitatively similar to those trained with visual or auditory cues. These results are in marked contrast to those obtained in respondent conditioning of aversions where taste cues are much more effective than olfactory, visual or auditory cues.