Lean Manufacturing (LM) is a concept that is comprehensive in nature and includes a set of many useful methods and tools. Despite the fact that a number of publications highlight measurable benefits related to the implementation of lean, plenty of companies still fail to implement or take any action with respect of LM. For the above reasons, based on existing research described in subject literature, a cognitive gap in the form of a time factor, which significantly affets the perception of barriers connected to the implementation of lean tools, has been identified. Thus, the purpose of this article is an analysis of perception of LM by companies that are before and after implementation of lean tools with reference to four selected cognitive areas. In order to achieve the scientific objective, a CATI survey has been conducted in Polish manufacturing companies, operating in Zachodniopomorskie Province. The research questionnaire has been divided into four parts and included: identification of internal and external barriers, knowledge of lean tools, awareness of expected benefits resulting from the implementation of Lean Manufacturing and plans to implement lean in companies in the near future. Selected methods of multidimensional comparative analysis have been applied. The results have been summarized, compared and discussed.