This chapter examines the trends in urbanisation, shows the reader what the urban system looks like and raises the issues and main challenges of urban areas in Poland. The chapter considers different definitions of urban areas and explores those applied in Poland. It also proposes and applies a methodology to identify urban areas based on their functionality and not based on administrative boundaries. The methodology identifies groups of urban functional areas (ULMAs) in Poland based on a series of indicators as well as on population size. The chapter also shows economic performance trends among ULMAs and discusses determinants of economic growth. Four main challenges are identified for urban areas in Poland: ageing and a shrinking labour force, inequality, transport infrastructure backlogs and the housing deficit. The chapter ends with a discussion on environmental pressures and the impact urbanisation has had.