Abstract: The effects of Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA) on cardiac hemodynamic and contractile parameters have been well established. On the other hand, the effects of Conjugated Linoleic Acid (CLA) on cardiac hemodynamic and contractile parameters and have never been investigated. The aims of this study were therefore to investigate the effects of CLA on these parameters in isolated rat heart and cardiac myocytes and to compare its effects to those of EPA and DHA. To investigate the effects on hemodynamic parameters, the aortic stump was cannulated and the heart was perfused with Tyrode’s solution. A latex balloon was inserted into the Left Ventricle (LV) to measure LV Pressure (LVP) and Left Ventricular Developed Pressure (LVDP). The results showed that both 20 μM EPA and 20 μM DHA significantly reduced increases in LVP and LVDP induced by 0.1 mM ouabain, an inhibitor of Na⁺-K⁺ pump. Unlike EPA and DHA, 10 μM CLA further potentiated increases in LVP and LVDP induced by ouabain. To investigate the effects on contractile parameters (i.e., [Ca²⁺]_i), propagated waves of calcium release in myocytes loaded with fluo 3 were imaged using laser scanning confocal microscopy. Imaging of the waves of calcium release showed that the amplitude and the rate of propagation of the wave did not increase in CLA but showed an increase in the rate constant for decay of calcium wave profile. Thus, the data clearly suggest that the effects of CLA are opposite to those of EPA and DHA suggesting different mechanisms actions. Instead of decreasing cardiac hemodynamic and contractile parameters, CLA increases them. The mechanisms whereby CLA increases cardiac hemodynamic and contractile parameters are probably due to the inhibition of sarcoplasmic reticulum calcium uptake.