The elastic mechanical properties of the cardiac myocyte membrane has been evaluated in terms of membrane stiffness and elastic moduli defined by area compressibility and shear strain. The method employed incorporates a membrane patch clamp system and micropipette aspiration, whereby negative pressure is applied to the membrane in the 10-60 mm Hg range. Calibration of the micromanipulation technique, by erythrocyte membrane analysis, was measured against previously published results on the erythrocyte membrane. For both cardiac myocytes and erythrocytes, a remarkably linear stiffness index was established, accompanied by relatively discrete elastic moduli.<<ETX>>