Background/aim: The aim of this research is to investigate the clinical efficacy of hemoperfusion in the treatment of severe acute organophosphorus pesticide poisoning (AOPP). Materials and methods: Patients meeting the inclusion criteria were divided into Groups 1 and 2 according to whether hemoperfusion was applied or not. Group 2 was observed as the control group. Conventional therapy for AOPP was given to Groups 1 and 2. Besides conventional treatment, patients in Group 1 were also treated with hemoperfusion therapy. Cholinesterase activity and blood glucose concentration were tested before hemoperfusion and for the first 3 days afterwards. The recovery time of 50% cholinesterase was recorded. At the same time, the incidence and mortality of intermediate syndrome was observed and compared. Results: The incidence and mortality of intermediate syndrome in Group 1 was obviously decreased, and the recovery time of cholinesterase activity was significantly shortened compared with Group 2. Conclusion: Hemoperfusion, used for treating severe AOPP, contributes to the improvement of cholinesterase activity, low incidence and mortality of intermediate syndrome, and increase in curative rate.