Male and female Wistar rats, aged 3 months, were massively trained (3.5 h) for a two‐way avoidance task and tested for retention (30 min) the following day. Some of them were subjected to a brief test (30 min) at 5, 10, 15, and 20 months. At 3 months, male rats scored more avoidances and a lower number of escapes, freezings, and intertrial crossings than females; in the test session, both groups improved their performance. Over time, male rats maintained the avoidance score displayed at 3 months. Female rats improved their performance at 5 and 10 months and then, at 20 months, they returned to the level attained at 3 months. These data suggest that active avoidance learning in young animals is fixed as permanent functional changes in the neuronal network of the brain which make aged rats, as well as young adult rats, able to master the task.