The novel multitargeted antimetabolite pemetrexed (Alimta), recently approved by the US Food and Drug Administration for the treatment of mesothelioma when combined with cisplatin, is also active in first- and second-line non-small-cell lung cancer (NSCLC). In a phase III trial comparing single-agent pemetrexed vs docetaxel (Taxotere) as second-line therapy in advanced NSCLC, survival was shown to be comparable between these agents, but side effects were significantly less frequent and severe for patients who received pemetrexed. In the frontline setting, phase II studies have shown significant activity and a very favorable toxicity profile of the combination of pemetrexed with a platinum agent. Pemetrexed has been well tolerated at systemic doses as a radiosensitizer when given as concurrent chest radiation, and a phase I study is under way to assess its tolerability in combination with carboplatin (Paraplatin) in this setting. Pemetrexed is an important addition to the armamentarium of medicines used to treat thoracic malignancies, and merits study in combination with other drugs having novel mechanisms of action.