Due to increasing complexity in the design process, the design and engineering sectors productivity has barely increased at all. A survey to employees of planning firms and a client organization confirms the need for change of the current situation in design and engineering. This thesis addresses the increase in efficiency of industrial building projects design phase by using Lean principles. The fundamentals of Lean and the current state of research in Lean Design is described. A Lean Design method as control tool for process planning in design phase is developed by using the Lean approach, the current level of Lean Design and the proved approach of Lean Construction. The thesis result is a guideline for practical implementation of a Lean Design method in industrial building projects design phase.