In three experiments, the study examined the ontogeny of latent inhibition in a conditioned taste aversion paradigm. In the first experiment, 18-, 25-, and 32-day-old rats received a pairing of a 0.6% Sanka solution with a LiCl injection (.75% BW, .4M) or physiologically balanced saline injection after either 4 preexposures to the taste or control treatment without taste preexposure. Experiment 2 investigated the possibility that a failure to observe latent inhibition in 18-day-old resulted from the particular experimental parameters employed in Experiment 1. In Experiment 2, taste exposure durations were longer, the retention interval between conditioning and testing was shorter, and deprivation conditions were more typical of those used with preweanling subjects. In Experiment 3, the study examined the effect of sham or fornix lesions at 18 days of age on latent inhibition at 32 days of age. Lesioned subjects exhibited equivalent conditioned taste aversions but failed to show latent inhibition.