Pemetrexed (Alimta , LY231514) is a new multitargeted antifolate that inhibits several enzymes involved in the folate pathway. Pemetrexed is a potent inhibitor of thymidylate synthase, dihydrofolate reductase, and glycinamide ribonucleotide formyltransferase. Pemetrexed has demonstrated clinical activity in non-small-cell lung cancer (NSCLC) as well as in a broad array of other solid tumors including mesothelioma and breast, colorectal, bladder, cervical, gastric, and pancreatic cancer. In NSCLC, single-agent activity has been documented in the first- and second-line settings. Promising activity has also been demonstrated when pemetrexed is combined with cisplatin, vinorelbine, oxaliplatin, carboplatin, and gemcitabine. Low-level dietary supplement of folic acid and vitamin B12 has significantly improved the safety profile of pemetrexed without compromising its antitumor effect. In this review, the pharmacology and clinical activity of pemetrexed in NSCLC cancer is discussed.