Excess female mortality has existed throughout Chinese history. Since the 1980s the sex
ratio at birth has risen significantly, resulting in a severely unbalanced sex ratio in the Chinese
population. Data from the five censuses, with appropriate adjustments, permit estimates of the
numbers of missing females from the period 1900–2000. The analysis is broken down by
historically important periods and probes the reasons for the missing females in each period. Our
estimates are compared with those of other investigators.