The efficiency of the construction industry in Sweden has been criticized for some time. As a response, many construction companies are now trying to streamline their production in different ways. The company JM is no exception and can be said to be in the forefront of introducing lean construction in the organization. JM call their system structured production. Lean Construction is a development of the lean concept originated from Toyota’s Production System. It is a world-known concept to make any kind of organization more efficient by minimizing non-value adding activities, often denoted as waste, from the business process.This report presents a case study of the implementation of JM:s structured production on the construction site. A questionnaire was sent to a large number of supervisors to investigate the use of structured production methods. Their responses indicated a positive attitude towards JM lean concept of structured production, but it was also shown that assembly instructions that is a part of the lean concept are not always applied. The main reason was that the instructions were not suited to all JM's project and that it was considered that some of the assembly solutions could have been made better. The reason for this response are shortcomings in the instructions but could also be an indication of lack of understanding for the lean philosophy. In order to improve compliance to the use of instructions the recommendation to JM is to educate their supervisors and craftsmen in the lean philosophy so they can actively contribute to JM structured production and the improvement of the assembly instructions.In order to follow-up the implementation of structured production a method to estimate the work carried out using the assembly instructions was proposed. The measurement is based on the compliance of the performed activities according to the assembly instructions. The results can be presented separately for each assembly instruction in order to improve the methods or compiled in a performance measurement of the level of implementation of JM structured production. The method is intended to be used by JM in their follow-up of structured production.