Cardiac morphology and function were determined by echocardiography in normotensive offspring of 23 hypertensive and 22 normotensive families. The family histories of hypertension or normotension were based on 27 years' observation of parental blood pressure. Pulsed Doppler and M-mode echocardiography were performed in standard views. Out of the total 109 offspring, 94 participated in the present study (age (mean +/- SD) 36 +/- 7 years). Left ventricular posterior wall thickness was higher in offspring of hypertensive than normotensive families (10.1 +/- 1.7 vs. 9.3 +/- 1.5 mm; p < 0.05). Offspring of hypertensive families had lower transmitral early/late peak flow velocities (p < 0.001) and higher transmitral late peak flow velocities (p < 0.001) than offspring of normotensive families, but the differences between groups became inconsistent after adjustment for confounding variables (including left ventricular structural parameters). On the other hand, the family history of hypertension was consistently associated with increased transmitral early peak flow velocity and increased transmitral acceleration and deceleration slopes p < 0.05), a pattern suggesting increased left ventricular stiffness. Increased posterior wall thickness and diastolic functional changes may indicate cardiac hypertrophy and decreased left ventricular compliance and precede the development of hypertension in offspring of hypertensive families.