Two experiments were conducted to test the hypothesis that rats with lesions in the parabrachial nucleus of the pons (PbN) can acquire conditioned taste aversions only if the conditioned and unconditioned stimuli are presented close together in time. In experiment 1, rats with lesions in the medial PbN, lateral PbN or outside of the PbN (lesioned control), and unoperated control rats were trained to avoid Na-saccharin in a one-bottle test. In this procedure, a 5-min delay was imposed between the 15-min Na-saccharin presentation and an injection of LiCl (0.3 M, 1 % body weight, i.p.). Results showed that, after three Na-saccharin-LiCl pairings, all rats, except the medial PbN group, acquired a strong aversion to Na-saccharin. In experiment 2, the same rats were presented with LiCl (0.12 M) in their 15-min daily access to fluid on 3 alternate days. Although rats in the medial PbN group drank more LiCl on day 1 than rats in the other groups, they significantly reduced their LiCl consumption on day 2 and did not differ from other groups by day 3. Results are discussed in terms of possible behavioral and physiological mechanisms that might account for these phenomena.