This paper brings readers a study of Life-Cycle Assessment of thermal insulation panels made of the stems of fibre flax. This study uses cradle-to-gate system boundaries, which means that only growing and harvesting of flax and subsequent processing and manufacturing of the insulation material are included in the assessment. Transport between the facilities is also included, because it has significant impact on the results - the production facility is located in Czech Republic, but thanks to the costs main components (fibre flax stems and chemical additives) are grown or produced in various countries around the globe. The paper shows that production of such insulation material has environmental impacts comparable with other insulation materials. Conclusion of the paper includes discussion about share of individual parts of the production process (growing, harvesting, transport, processing and manufacturing) on the overall results and recommendations of changes that would lead to decrease the overall environmental impacts.