This paper examines Guangdong's fertility decline between 1975 and 2005 and analyzes how it has been influenced by both fertility policy and economic development. Guangdong's economic development has been very rapid and has attracted huge numbers of migrants from other provinces. The effect of this migration on Guangdong's fertility is an important part of the story. Measures of fertility and nuptiality employed in the analysis include the total fertility rate, parity progression ratios, mean age at first marriage, mean age at first birth, and mean closed birth interval between first and second birth. These measures are calculated from birth histories reconstructed from data from China's 1990 and 2000 censuses and 2005 mini-census. An overlapping-trend analysis provides indications of the accuracy of the estimates.