In 1988 and 1989, mammography topped the list of new state mandates for health insurance benefits. Following the lead taken by Maryland in 1986, over half of the states now mandate insurance benefits for breast cancer screening through the use of low-dose mammography. Mammography is one of several preventive and diagnostic procedures, together with cytology screening, well-baby care, child health supervision, and colon and rectal cancer screening, that has become an increasingly popular category of mandated benefit. The number of mandated benefit laws in all categories has rapidly multiplied since the early 1970s. The earliest of these covered specific medical conditions and diseases or the services of allied health practitioners; preventive or diagnostic services, such as mammography, are more recent coverage phenomena. State governments, responding to demands for coverage from a public preoccupied with wellness and expecting the maximum health care treatment intervention to be available and accessible in all cases, are clearly willing to use their authority to regulate the insurance industry so as to expand and improve access to health care services. Despite new concerns over the cost of mandated benefits generally and budget woes in many jurisdictions, the states' interest in improving access to preventive health services, such as mammography, remains strong as we enter the 1990s.