Companies seeking to implement lean practices in engineer-to-order environments experience major difficulties due to a high degree of non-standard products and non-repetitive processes. Current lean methods need to be further developed to be more efficiently applied in manufacturing environments with high variety and complexity. This paper presents a new approach for value stream mapping adapted to engineer-to-order production systems. The approach combines the classic value stream mapping approach with recent works dealing with lean methods in high mix and complex production systems. Also, it proposes a stronger focus on the choice of location of the customer order decoupling point compared to previous research.