1. The predictions of the marginal value theorem, that foragers should spend more time in both better quality patches and more distant patches, were tested with three European ant species, Lasius fuliginosus, L. niger and Myrmica ruginodis. 2. As the quality of patches of sucrose solution increased, the feeding time of foraging workers of L. niger also increased. 3. At constant patch quality, feeding times of L. niger and M. ruginodis increased with increasing distance of the patch from the nest entrance. 4. Foraging workers of L. fuliginosus showed a similar response to patch distance in the field, but feeding times were also significantly influenced by air temperature, decreasing as temperature increased. 5. These results show qualitative agreement with the predictions of the marginal value theorem.