The purpose of this thesis was to create a deeper understanding on the way in which Swedish companies internationalize their business activities in the U.S market and the impact that the business environment has on their further evolvement in the market. To create a deeper understanding of the area, a qualitative research has been conducted. The primary data has been collected through case studies with Swedish business-to-business (B2B) companies who have established their business in the U.S market. In order to gain a basis for further examination of the subject a theoretical framework has been established. The theoretical framework is based on existing theories related to internationalization, barriers and networks and is formulated through a model in order to illustrate how these theories are connected. The empirical chapter gives a presentation of the primary data with a focus on the areas internationalization, uncertainty and barriers. The collected empirical data is further discussed in the analysis chapter where the aim is to analyze the information from the participants in the cases and identify common patterns as well as explaining the choices with the theories. Based on the analysis made, several conclusions could be drawn. Swedish B2B companies internationalize in incremental steps and evolved in accordance with the establishment chain in the U.S market. One of the factors to the successful evolvement is the network they entered or created in the U.S market. The business environment, more specifically the political environment, is a barrier for the companies evolvement and at the same time is uncertain.