Nemone Tehran Poultry Slaughterhouse with an area of 13000 m² is located in Region 3 of District 5 of Tehran Municipality, in the Morad Abad quarter. The current research aimed to assess environmental impacts caused by the slaughterhouse operations. To do this, the methods Scaling-Weighting Checklist and Analytic Hierarchy Process (AHP) were integrated. The required criteria and potential options were initially identified using the Scaling-Weighting Checklist method through analyzing the project impacts. Delphi questionnaire was applied to finalize the introduced criteria.  After drawing the hierarchal structure and pairwase comparison of the criteria, the Eigenvector technique was used to prioritize the criteria and options in the environment of the Expert Choice software. In order to obtain the total index, the criteria weights were firstly multiplied by the criteria scales in each option of the checklist, and then the resultant values were added up. The results obtained from analyzing the slaghterhouse effluent quality showed that it is not suitable to be discharged into the surface water or wells. It is not also suitable for irrigational and agricultural purposes. Noise assessment results revealed that the measured noise is beyond the permissible noise level in the ambient air. The results of air pollution suggested that the amounts of the parameters NO₂, SO₂ and CO are lower than the standard presented from emission of stack and environmental standards. After determining the weights of criteria in terms of the slaughterhous pollution, the first priority was given to the wastewater criterion with a weight of 1.278. Noise, air and odor pollution with a weight of 0.261, 0.216 and 0.091, respectively, were assigned as the next priorities. The socioeconomic and cultural environment with a weight of 0.699 obtained a higher rank compared to the physicochemical and biological environments which were weighted 0.237 and 0.064, respectively. The health criterion was weighted 0.783 with the highest priority in the socioeconomic cultural environment. The optimization of the wastewater treatment system as well as constant monitoring of the effluent quality were proposed as the most  important  practices which may mitigate  the adverse impacts  caused  by the slaughterhouse.