In this study, we evaluated the effects of treated effluent of Khuzestan Pars Paper Industry (0.5% and 1%) on liver biochemical factors of Alburnus mossulensis during 21 days. There were significantly increased aspartate aminotransferase, lactate dehydrogenase and creatine phosphokinase levels observed in fish after a 21-day exposure to treated effluent. Alanine aminotransferase, alkaline phosphatase and total protein significantly decreased in liver tissue after exposure to effluent of Khuzestan Pars Paper Industry (P<0.05). Based on these results, although it seems that Pars Paper Industry can discharge into rivers, however these results have shown that the effluent could have dangerous effects on the health of aquatic organisms.