Every company (including machinery manufacturing and construction companies) leads to increase its activities' profitability and to improve quality performance indicators, such as processes operating and safety culture, safety level, human resources satisfaction level, and goodwill. Lean manufacturing and lean construction (derivative of lean manufacturing) enable to reach these goals. The article reviews methods of company efficiency increasing potential evaluation and aims to help in choosing the most important improvements fields. Upon the review results the article authors propose the efficiency improvement potential evaluation model for machinery manufacturing and construction companies based on lean manufacturing.