Overall suicide mortality rates are higher among American Indians than in the general population and are particularly high among Indians residing in the upper Midwest. The identification, during encounters with health care providers, of individuals at high risk of suicide is a potential intervention strategy. The purpose of this study was to examine whether increased health care utilization and symptom patterns were associated with suicide and suicide attempts among American Indian patients in an Indian Health Service facility. A case-control study design was used. Cases of completed suicides over a 6-year period and cases of suicide attempts over a 15-month period were identified on a Plains Indian Reservation. The pattern of utilization of health services by these subjects prior to their suicide or attempt was compared with that of control subjects matched for age and gender. Only 24% of subjects who died of suicide used the reservation clinic or hospital for services in the 6 months prior to their suicide, compared with 54% of controls (odds ratio [OR] 0.28; 95% confidence interval [CI], 0.09, 0.87). The patterns of symptom complaints and diagnoses for these visits did not differ significantly between case and control subjects. Case subjects who attempted suicide were more likely to be seen during the 6 months prior to their attempt than control subjects (57% vs 40%, OR 1.72; 95% CI 0.75, 3.93). Persons who attempted suicide were more likely to have documentation of psychological and interpersonal problems than were control subjects. Only 14% of subjects completing suicide had a previous history of suicide attempts. In this region, American Indians who committed suicide were less likely to use clinical services provided by the Indian Health Service prior to their death. However, there was a relatively strong association between suicide attempts and the prior use of health services, particularly the use of mental health services. In this American Indian population, clinic-based methods for early detection and intervention to prevent imminent suicide would reach fewer than one fourth of suicide victims. Further research is needed to identify the usefulness of community outreach efforts to identify and intervene among individuals at high risk of death by suicide.