The present invention relates to a stable liquid pharmaceutical composition of pemetrexed for parenteral administration. The invention provides composition comprising pemetrexed diacid, an organic amine and cyclodextrin. The composition may further comprise an inert gas. The composition can be ready to use infusion solution of pemetrexed diacid or liquid concentrate formulation to be diluted before administration to the patient. The present invention further relates to a process for manufacturing the compositions as well as use of the compositions of the invention for the treatment of malignant pleural mesothelioma and non-small cell lung cancer.
