Efficacy of pemetrexed has been demonstrated in malignant pleural mesothelioma. This is based on the result of a phase III trial comparing cisplatin and pemetrexed to cisplatin alone, with a significant improvement of median survival in the doublet arm (11.4 versus 8.8 months, p = 0.048). This combination represents a new standard of chemotherapy in this disease. In non small cell lung cancer, pemetrexed has been compared as second line chemotherapy to docetaxel : efficacy was comparable (median survival of 8.3 months with pemetrexed and 7.9 months with docetaxel) but significant less hematological toxicity was observed in the pemetrexed arm compared to the docetaxel arm, especially grade 3-4 neutropenia (respectively 5.3 and 40.2%) and febrile neutropenia (1.9 versus 12.7%). The place of pemetrexed in elderly patients is under evaluation.