This paper presents urban dialect as a determining factor of local identity. The author analyses the definitions of dialect and shows the changing perception of this concept, as well as its nature and the current role. Regional identity and its correlation with the dialect is also addressed. The present considerations are explored through the example of the present-day urban dialect of the city of Poznań, which, despite of decreasing number of active users, shows an increase in popularity and willingness to cultivate it in forms that allow the language to be perceived in terms of regional identity. Local dialect of the city of Poznań is analysed in a historical context, showing the significant influence of the German language and the economic and social changes of the city on the language formation. The paper also investigates urban dialect from a modern perspective, discussing its appearance in radio, texts and books.