Designers are facing the principle problems of effective decision making at initial design stage of product development, which ultimately cost it in the form of profit loss, low quality and increased time to bring the product to market. It needs a lot of knowledge and experience. Tools are required to analyze and ensure that crucial decisions have strong foundation before implementation. Discrete event simulation provides such a tool and has got potential to provide assistant in decision making before final implementation. This research work aims to measure the benefits of transformation to lean product development (LPD) via simulation. Simulink-MATLAB tool was used for this purpose. The whole work is limited to design and cost estimation cells of a manufacturing company and consists of two phases. The first phase deals with the assessment of current working model of design and cost estimation cells. Areas for improvements were recognized at this phase. The proposed model for transformation to LPD was developed in second phase. Four lean enablers naming product values, knowledge-based engineering, set-based concurrent engineering and poke-yoke have been incorporated to further enhance the working of proposed model. This research work is quite a useful case for practitioners.