Despite lean thinking begin a broadly accepted approach,there is still some confusion within terminology regarding 'lean' and its issues.This paper presents the results of a research survey carried out within 72 medium and large-sized Slovenian manufacturing companies. the sample selection criteria adopted, together with the research items investigated, ensured a generic framework for our research. Eight crucial areas were identified based on a synthesis of 'lean' literature for assessing and measuring the degree of lean implementation within existing manufacturing systems: value concept and customer,value stream mapping (VSM),pull/kanban and flow, waste elimination,productive maintenance, Just-in-time (JIT), employee involvement and the development of excellent suppliers (lean suppliers).