Abstract
In this paper there were presented some issues connected with Lean concept in improving of production processes. The research was conducted on the example of production enterprises that function in metal industry. The enterprises for the research were chosen purposefully, because of two reasons - the possibility to obtain information on the researched area and the assumption that these enterprises use the lean concept instruments. The questionnaire was the research tool. The goal of the research was to examine, what are the most expected advantages from implementing of lean concept methods, and what were the real advantages, that occurred in production system of researched enterprises. The authors presented the quantitative results of the study and carried out an analysis of the response in the form of a matrix. The developed matrix extended the knowledge about the distribution of observed benefits. It enables to indicate which advantages occurred in the enterprises expecting and not expecting some benefits.