This paper presents and discusses a case study of health legislation in China. In the transition to a market economy, legislation has been developed to offset the weakening in the central planning mechanism and political control that have historically influenced the behaviour of institutions and individuals in the Ministry of Health. There has been relatively little empirical examination of the implementation and impact of legislation as a tool for influencing health service provision in low-income countries. The study aimed to contribute towards filling this gap by exploring the factors affecting the implementation and impact of the Maternal and Infant Health Care Law, through a case study of two poor, rural counties in Chongqing municipality, China. The study found that key local actors perceive health legislation to be an important tool for safeguarding access to essential health care. However, the implementation of health legislation is inevitably a political process. The study illustrates the difficulties involved in efforts to influence provider behaviour through a national level legislative framework in a situation of decentralization of control over those providers, due to extreme regional variation in economic situations and limited resource inputs from the centre. Lessons are drawn for Chinese and international policy makers.