Medical genetic services for the care and prevention of congenital disorders have received little attention in most middle- and low-income countries to date. In 2010, the World Health Organisation prioritized services for the care and prevention of birth defects in these nations, emphasising their importance in assisting such countries to reach their Millennium Development Goals. Health Needs Assessment is an inclusive, rational, epidemiological-assisted approach for providing information to plan, introduce and beneficially change health care services to improve the health of populations. It is intrinsic to much of the development of health care systems in industrialised nations. Its use by middle- and low-income countries to introduce and develop medical genetic services commensurate with their needs and circumstances would be beneficial. An approach to applying Health Needs Assessment in these circumstances is described.