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Background and aims: This is a descriptive and cross sectional study. The aim of this study was to investigate the environmental ranking of industries located at west of Tehran based on the quantitative and qualitative characteristics of industrial wastewaters in 2011. Methods: This study was conducted by site visit, questionnaire completion, database production and results analysis. The questionnaire was consisted of 30 questions about quantity, quality and management of industrial wastewater. Total number of industries with over than 50 personnel, was 287. Class-weighted sampling was used and the sample size was contained 50 industries. In this study, industries were scored from 1 to 10, based on the flow rate, BOD and COD, generation of wastewater per worker per day and then were ranked according to the total score. Results: The average flow of wastewater generated by these 50 industries was 9422 m3/day. Wood and cellulose industries with 730 liters wastewater per worker per day was considered as the greatest wastewater generator. Minimum organic loading was related to non-metallic mineral industries with COD of 205 mg/ L and BOD of 85 mg / L. The maximum COD was related to paper industries with the rate of 8800 mg/ L and maximum BOD was related to food and drug industries with the rate of 1536 mg/ L. Conclusion: This environmental ranking was indicated that while paper industries contributed the most pollution load, non-metallic mineral industries had the least pollution load. [ABSTRACT FROM AUTHOR]