Internal communication in organization is a key point for a successful and efficient business in the times of changes. In my master thesis I studied the concepts of organization, social structure of organization, organizational communication, internal communication and organizational changes on the case study of selected company. The selected company is one of the most successful and recognizable companies in the field of manufacturing motor and automotive parts. The company went through some major changes in the last few years, including moving part of the company, which had a strong impact on employees and the internal communication strategy was necessary. Through my case study I am trying to identify if the internal communication in the selected company in times of major changes was successful and if this internal communication contributes to successful realization of moving. At the end I give some proposals for improvement of internal communication in selected company, based on collected internal documents, interviews with the management of the selected company and analysis of questionnaires on employee satisfaction with internal communications in the selected company.