China’s urban population has experienced rapid fertility decline over the past six decades. This drastic change will have a significant impact on China’s demographic, social and economic future. However, the patterns and characteristics of urban China’s fertility decline have not been systematically examined. This study analyses the trends and age patterns of fertility in urban China since the 1950s, and summarizes the major characteristics of reproductive behaviours into four ‘lows’: extremely ‘low’ level of fertility; ‘low’ proportion of two and higher parity births; ‘low’ mean age at birth; and ‘low’ level of childlessness. The paper argues that the highly homogenous reproductive behaviours found in China’s now near 800 million urban population have been in part shaped by the country’s unprecedented government intervention in family planning. The ‘later, longer, fewer’ campaign in the 1970s and the ‘one-child’ policy, in particular, have left clear imprints on China’s reproductive norms and fertility patterns. The government-led family planning programme, however, has not been the only driving force of fertility decline. A wide range of social, economic, political and cultural changes have also affected the transition in family formation, reproductive behaviour and fertility patterns, and this has become increasingly prominent in the past two decades.