After the past of two decades of lean manufacturing (LM) introduction in Iran, instead comparing this concept with industry as a culture, it is used as tool for improvement. Without doubt, LM as one of the most strong of quality improvement systems is countered by barriers and problems. One of main tasks of top management is identification and ranking the LM barriers for comparison by important barriers. This research identifies the key barriers in successful implementation of LM. Although the country researchers to point some implementation barriers of LM, But they have not studied the total literature of these barriers, also the relationship between barriers and finally ranking of them.

For this purpose, after the literature review and interview with experts of gas industry, 7 barriers (as 7 secondary hypotheses of research) were identified in successful implementation of gas industry, and they were confirmed with validity. Then by distribution and gathering of 170 questioners and using statistical tests (Kolmogorov-Smirnov and mean), the main hypothesis of this research and 7 secondary hypotheses were confirmed. Finally, the relationship between barriers and their ranking were studied using fuzzy DEMATEL model. According to this model and done ranking, a practical program was proposed for comparison by implementation barriers of LM in gas industry.