The first study on DIC export and and carbon emission from the Tigris River. The mean value of pCO2 (1277 µatm) was lower than global river averages. There was a positive correlation between pCO2 and phytoplankton abundance. Water-to-air CO2 degassing flux from the Tigris River was around 39 mol/m2/y. Annual emission of 0.15 Tg C as CO2 was 0.6 fold the riverine DIC flux.