Minnesota Multiphasic Personality Inventories (MMPIs) of 36 patient suicides (20 males and 16 females) were compared with two matching control groups, one of 36 highly suicidal patients, the other of 36 nonsuicidal patients, each matched with the suicide group by age and sex. Female suicides differed significantly from all male groups and from both female control groups. Female suicides had higher Mf, Si, and Hy scores and lower K scores than the highsuicidal female controls, suggesting nondefensiveness, a more masculine interest pattern, social withdrawal, and denial and repression of inner needs and feelings. Male suicides were significantly differentiated from nonsuicidal males but not from the high-suicidal male controls. Nonsuicidal males had higher K and OH scores and lower Mf and D scores than the other two male groups, suggesting a more active, assertive, and self-protective stance. These differentiating patterns emerged from a population of voluntary psychiatric patients and would not necessarily be generalizable to other populations. The study emphasizes the necessity for knowing the population and the subgroups within; once these measures are taken, MMPI patterns appear to have usefulness in predicting suicide potential.The Minnesota Multiphasic Personality Inventory (MMPI) has been studied for some time as a possible predictor of suicide with encouraging results but with limited populations and an obvious need for further study (