This graduation thesis researches the role of organizational culture in the merger of two construction companies from which a new construction company named LafargeHolcim was founded. After the theoretic approach regarding organizational culture and integration processes, the thesis analyzed the core dynamic of the before named merger process and the role of organizational culture throughout the whole integration period. The data for the analysis was collected by a quality method, namely an indepth interview. The analysed data showed that the new found company has retained positive values, from every participant a few, what represents a common ground towards a new mutual business. The lack of communication within the hierarchy changed the old, strong and clear organizational culture into a new, strong, unclear and adaptive organizational culture. Organizational culture makes an inpact on the new image of the company, on the relationship between all the members of the new company and in return it creates a new sense of organizational identity and commitment. These elements are crucial because all the employees in the company have a clear reason why they work, for whom they work and why they exist on the market. This new construction company has a healthy and strong organizational culture but it will take some more time that it becomes clear to every single member within the organization.