AIMS: Increased access to health care, including addiction treatment, has long been a goal of health reform in the U.S. An unanswered question is whether reform will change the way people get to addiction treatment; when treatment is easily accessible, do individuals self-refer, or do they still enter treatment via ultimatums, and if so, from which sources? To begin examining this, we used a single case study of a U.S. health plan that provides access similar to that called for in health reform. METHOD: Using a case study method of data from studies conducted in a large, private non-profit, integrated managed care health plan which includes addiction services, we examined the prevalence and source of ultimatums to enter treatment, and the characteristics of those receiving them. The plan is highly representative of changes to U.S. health care and other countries due to health reform. RESULTS: Many individuals entering addiction treatment had received an ultimatum stemming from employment, legal, medical, and family sources. Having more employment problems, an occupation with public safety concerns, being older, male, and ethnicity predicted an employment ultimatum. Higher legal problem severity predicted a legal ultimatum. More men (and younger people) had family ultimatums, and more women (and older people) had medical ultimatums. Being younger, male, married, having higher employment and family problem severity, and being drug or combined drug/alcohol dependent rather than dependent on alcohol-only predicted an ultimatum from one's family. On the whole, an ultimatum from one source was not related to having one from another source. Those most likely to receive ultimatums from multiple sources were women, those separated/divorced, and those having higher psychiatric and legal problem severity. CONCLUSIONS: Even in an insured population with good access to addiction treatment, individuals often receive ultimatums to enter treatment rather than being self-referred. Understanding the treatment entry process, and how it is affected by health care systems, could benefit from international and other comparative research.