M-mode echocardiograms were obtained on unmedicated males with mild hypertension before and after treatment with thermal biofeedback, autogenic training, or self-relaxation. Although patients for whom diastolic blood pressure (DBP) was successfully reduced showed trends toward reduction in left ventricular parameters while unsuccessful patients showed no changes, the results were not significant. For the four patients with borderline left ventricular hypertrophy, there was a strong trend (p = .06) for successful treatment to lead to a reduction in left ventricular mass. Moreover, across the whole sample, reduction in left ventricular mass was related (r = .30) to decrease in DBP.