The role of corticotropin-releasing factor (CRF) in mediating the stress response was studied using a behavioral test in which anxiety or conflict influence performance. Rats implanted with intraventricular cannulae were tested in a Geller-Seifter conflict test modified for incremental shock. CRF produced a dose-dependent attenuation of punished and nonpunished responding in the conflict test. Chlordiazepoxide increased punished, but not unpunished, responding and produced a dose-dependent reversal of CRF-induced response suppression. CRF had no effect on tail flick or hot-plate analgesia tests. The results support the hypothesis that CRF produces behavioral effects consistent with "anxiety" or an increased responsiveness to stress.