Background: The Industry 4.0 initiative is a synonym for the ongoing fourth industrial revolution that takes place in a variety of industrialized countries. While the topic is considered to be of high relevance, it is still in an early development phase. It is uncertain, how the new, but very different concept impacts companies and which sub-concepts of the Industry 4.0 initiative will prove themselves as being useful. The potential of Industry 4.0 and its associated technologies are a general part of the current discussion, but the question arises if businesses that have heavily focused on lean practices in the past can combine these methods with the sub-concepts of the nascent fourth industrial revolution. The origin of lean principles dates back to the 1950s. Initially, these methods were not meant to take possibilities of modern information and communications technology that are available today, into account. 

Purpose: The purpose of this thesis is to draw attention to a possible combination of consisting lean practices and the aforementioned concept of the fourth upcoming industrial revolution. In order to gain a thorough understanding, the components of Industry 4.0 will be examined and its possible influence on a business as well as a potential combination with lean practices will be investigated. Our study is of importance, as it ascertains a possible future scenario of both concepts on which businesses can rely. 

Method: The presented study used a qualitative research method in the process of gathering information and data pursuant to the topic. Further, a multiple case study strategy was carried out, which incorporates ten interviewees from seven companies of different industries. The majority of data was gathered from semi-structured interviews, while documentary secondary data was used to conduct basic information of the companies. The frame of reference together with the interviews demonstrates how reality correspondents with the literature. 

Conclusion: Industry 4.0 is often used for marketing purposes by the automation industry. Yet, the concept needs to be defined clearly so that companies understand the truthful meaning of this particular initiative. Sub-concepts that influence companies are Cyber-Physical Systems and Internet of Things, whereas Internet of Services is used occasionally. At the certain moment, Smart Factories do not influence either industries or particular companies. An Industry 4.0 implementation within the organizational structure is only feasible with lean practices. Lean is an omnipresent concept that will continue to impact different industries in the future. Both concepts will work together as they strive for the same goal to achieve a financial benefit for any company.