Using secondary data analysis, this paper examines the societal impact of mainland Chinese expectant mothers who gave birth in Hong Kong (HK). In 2009, 45.4% of live births were born to this group of women, compared to 10.2% in 1995. These women agreed unanimously that giving birth in HK would secure the future of their child with permanent residency, access to free education, subsidised health care, social welfare benefits and a better standard of living. For parents who choose to have more than one child, cross-border birthing can provide an opportunity to bypass China’s one-child policy. This rising trend has put heavy pressure on the already stretched obstetric services at the expense of local women. The Hospital Authority (HA) responsible for public hospitals acknowledged that in the 2004-5 financial year, 1 670 mainland women failed to pay HK$12.64 million (USD1.63m) in hospital bills; and in 2005-6, 2 138 women defaulted HK$28.58m (USD3.68m). In response to protests at this situation and the lack of an effective policy, HA introduced an obstetric package in February 2007. Non-local expectant mothers must now pay HK$39 000 (USD5 000) in advance to cover one antenatal visit, delivery service and delivery-related hospitalisation for three days; non-compliant women would be charged HK$48 000 (USD6 154). Mainland women who are over 28 weeks’ gestation are now denied entry at immigration checkpoint if they do not have a prior booking. Between February and December 2007, an HA audit showed a 229% increase in booking for public hospitals alone and secured HK$257.4m (USD33m) in fees. Non-compliant cases and last-minute hospital admissions were significantly reduced. In addition to the high bill settlement rate, this policy has provided a steady workload and training opportunities for many health care providers. If these new citizens remain in HK, they may contribute to the prosperity as well as alleviating the ageing population of HK.