Tiflucarbine is a structurally novel antidepressant that binds at central serotonin (5-HT) binding sites. There is also evidence that this agent is both a 5-HT1 and a 5-HT2 agonist. To further characterize the serotonergic actions of this agent, tiflucarbine was evaluated in groups of rats trained to discriminate the 5-HT1A agonist 8-OH DPAT, the 5-HT2 agonist DOM, and the nonselective 5-HT agonist 5-OMe DMT from saline. Tiflucarbine resulted in partial generalization in the DOM-trained and in the 8-OH DPAT-trained animals. Although two-thirds of the animals were disrupted, 10 mg/kg of tiflucarbine resulted in stimulus generlization in the 5-OMe DMT-trained animals. It is concluded that tiflucarbine is most likely a nonselective 5-HT agonist.