The purpose of this study was to determine which borderline hypertension subjects could succeed in self-regulating blood pressure, and to distinguish the psychologic and physiologic variables that predicted success. Thirty-four white, male, unmedicated, borderline hypertensive subjects participated in a 14-session biofeedback/cognitive selfmanagement training program. Of these, 22 exited with diastolic pressure below 90 mm Hg; 12 exited equal to or above 90 mm Hg. Both groups exited with scores markedly lower on the Symptoms Checklist-90 (SCL-90). The successful group began and ended on all cognitive/affective subscales at a lower level than the unsuccessful group. A discriminant analysis revealed that lower scores on the SCL-90, lower systolic blood pressures, and higher heart rates during a mental task at the beginning of treatment distinguished those who succeeded in self-regulation from those who could not succeed. The possible mechanisms for blood pressure control/change as a consequence of biofeedback are discussed.