This thesis focuses on building strong brands through brand image and brand identity. Therefore, an analysis of various factors that influence both brand image and brand identity was carried out. The most important of these factors are brand value and related brand value models, corporate social responsibility, and new trends in brand management as for example digital marketing, viral marketing, event marketing and sponsorship. The aim of the performed research is to identify the image of two most valuable sports brands, Nike and Adidas. Based on the results the image of both brands is compared and furthermore, a comparison of the Nike's brand image with its identity is performed