In the current study, the environmental impacts of tomato paste production were investigated based on the total life cycle of tomato including cultivation, processing, packaging and transportation, using the Centrum voor Milieuwetenschappen Leiden Impact Assessment, (CML-IA) method in Kermanshah regions. The required information was obtained through interviews, questionnaires and, Ecoinvent, LCA Food DK and IDMAT databases. Results showed that among the influential groups, during the production process of one kg of canned tomato paste, the ozone layer depletion and the reduction of organic resources were least effected and the open waters ecotoxicity received the highest impact. In the cultivation process, electricity consumption had the greatest impact on open waters ecotoxicity followed by the nitrogen fertilizer. The factory processing phase had the lowest impact among the influential groups (except open waters ecotoxicity). The energy efficiency was calculated as 0.63 kg/MJ. The net energy gain and the total energy consumption in the tomato farm were -42700 and 44.86 MJ/ha, respectively. The consumption of electricity and chemical fertilizers were the highest amount of input energies with 75.43 and 16.94% respectively. According to the results, the cultivation phase has the adequate potential to reduce the environmental impacts during the tomato paste production through the improvement of irrigation systems to reduce electricity consumption.