After the water- and steam empowered mechanization of manufacturing, the introduction of mass production based on electrical energy, and the first digitalization of industrial productions in the 1970s, currently a 4th industrial revolution is propagated - commonly referred to as "Industry 4.0". Based on Cyber-Physical Systems (CPS) and enhanced by modern Information and Communication Technology (ICT), Industry 4.0 should enable an entirely new approach to industrial manufacturing and serves as a means to strengthen Europe's and especially Germany's production industry (Acatech 2013). Although highly supported by political initiatives and increasingly acknowledged by scholars, the implementation of Industry 4.0-s "smart factories", "smart products" and "smart networks" fails to keep up pace with its political popularity. Current surveys indicate that - beside high investment costs - the high topic-complexity resulting in uncertainty is one core issue decelerating the realization. Consequently to the company's uncertainty, they fail to assess their own capabilities and maturity within the field of Industry 4.0, which disables from taking any coordinated measures towards successful realization. Tackling the outlined problems, this work suggests the so called "Industry 4.0 Maturity Model (I40MM)" - a model that allows companies to self-asses their capabilities in Industry 4.0 and, consequently reduces uncertainty which results in target-aimed development of road-maps in Industry 4.0. The I40MM is developed using a multi methodological approach including a systematic literature research and qualitative and quantitative survey research. The model is scientifically based on Hevner's design science approach (Hevner et al. 2004) as well as Becker's procedure model for the development of maturity models (Becker at al. 2009). In a first step, interviews were carried out with Industry 4.0-experts to highlight the practical need of the maturity model, capture the state of Industry 4.0 in real life and to support the domain-specific population of the I40MM. Simultaneously, a systematic literature review on "maturity models" resulted in more than 3400 findings and the consideration of 72 publications for inclusion into the model-s development. Also, no published maturity model applicable to the domain of Industry 4.0 has been found during the literature research, which supports the model's academic relevance. Afterwards, the model's practical relevance was validated by expert-ratings of the maturing items- practical importance (attributes) - resulting in 23 responds with an average importance rating of 3,2 (1 - not important, 4 - very important). Their rating was used for the weighted calculation of the 9 company dimension's Industry 4.0-maturity. The attribute's maturity-measurement within the company is surveyed using a newly developed questionnaire consisting of 62 questions (one question per maturing attribute) in 9 company-dimensions. To ensure good practical usability, the I40MM is transformed to a Maturity Report consisting of 11 pages, whereby the 1st page (Maturity Dashboard) summarizes the companies Industry 4.0 maturity at-a-glance. Finally, the I40MM has been pilot tested in cooperation within two companies. Feedback regarding usability and representability is positive throughout, which validates the model for real-life application. On an academic level, the novelty of the I40MM, as well as its strong scientific bases should lead to the model's acceptance among scholars.