The forced swim test assesses learned helplessness, which is a feature of depression-like behavior in rodents. This test has also been used in testing the efficacy of existing and novel antidepressant drugs. It is based on the natural tendency of rodents to escape from water. Rodents are placed in a cylinder filled with water and the presumption is that those with a depression-like phenotype give up swimming earlier than those that are not depressed. Furthermore, antidepressant drugs reverse this effect. This chapter describes the basic setup and conduction of the test, along with interpretation of the results. It should be emphasized that this test should be conducted as part of a series of behavioral assessments in order to increase the accuracy of the results.