Food-seaching workers of eastern yellow jackets, Vespula maculifrons, are attracted by the natural odors of a wide variety of succulent fruits; particularly effective was pear. The only part of a fruit that repelled was the leathery epicarp of oranges. After rewarding with sugar water, odors of six fruits, including the pulpy mesocarp of oranges and, in addition, the leaves of catmint Nepeta cataria, all become highly attractive. To learn the distinctive odors of any of three fruits (pear, apple, quince), nondiscrimination training with a rewarded fruit was sufficient for the subsequent olfactory preference of the training fruit over the control fruit. In the other cases [banana, hawthorn (Crataegus crus-galli), grape] simultaneous discrimination training with a rewarded and an unrewarded fruit was necessary and effective for obtaining differential responses to the odors of the training fruits. As far as current evidence goes, olfactory learning plays similar roles in the fruit foraging of this wasp and in the nectar foraging of the honey bee (Apis mellifera).