Faced with the challenge of a major health problem, the present epidemiological study was designed to identify new and emerging high-risk population subgroups, to pinpoint opportunities for early detection, and to suggest new measures that can be implemented in the practice of good preventive medicine. The analysis of the 236 suicides reported in Philadelphia in 1972 found that young black males as well as divorced persons of both sexes represent established high-risk population subgroups. In contrast to reports of high suicide rates among the elderly, there was no evidence of a direct linear increase in suicide risk with increasing age. Only white males showed a peak suicide rate in the oldest age group. Data from this study indicate increasing suicide rates for women. The current ratio of male to female suicides is about 2:1, in contrast to earlier reports of ratios about 3:1 8 and 4:1. 10 The disparity between rates of attempted and completed suicide by sex (women are overrepresented among attempters) is not due to any difference in suicidal intent. Our study found no differences by sex in scores on the Suicide Intent Scale, a behavioral measure of the seriousness of fatal and nonfatal suicide attempts. Factors involving access to the medical establishment and in particular to psychotherapeutic drugs are indicated in the preference for drug overdose shown by female suicides. Such drugs are highly available, but they have a relatively greater degree of medical rescuability when compared to other common suicide methods. An overall increase in suicide by drug overdose, and in particular the use of prescription drugs, suggests the need for public health legislation to require the inclusion of an emetic or some other agent as a deterrent to overdose in the widely prescribed psychotherapeutic drugs. Large numbers of suicides showed blood ethanol levels in excess of the legal definition of intoxication. Clinical experience with attempted suicides suggests that this is frequently due to reluctance, resistance, and fear of the suicide act, which is overcome only with the psychotropic effects of alcohol. Measurement of clinical psychological factors shown to be associated with suicide is now indicated. The high correlation between depression and suicide strongly suggests the need for widespread screening in family practice, using instruments now available for use in diagnosis of depression, such as the Depression Inventory. In addition, the variation in suicidal intent shows that intent is a dimension rather than a dichotomous decision. The use of measures such as the Suicide Intent Scale in hospitalized cases of attempted suicide would provide a good indication of future suicide risk.