The temperature dependence of soft tissue acoustic properties is relevant for monitoring tissue hyperthermia. In the current work, the propagation speed and attenuation of healthy porcine left ventricular myocardium (N = 5) was investigated in a frequency range relevant for clinical diagnostic imaging, i.e. 2.5–13.0 MHz. Each tissue sample was held in a water bath at a temperature T = 25 °C, heated to 45 °C, and allowed to cool back down to 25 °C. Due to initial tissue swelling, the data for decreasing temperatures was considered more reliable. In this case, the slope of the phase velocity versus temperature relation was measured to be 1.10 ± 0.04 m/s/°C, and the slope of the attenuation was −0.11 ± 0.04 dB/cm/°C at 10 MHz, or −0.0041 ± 0.0015 dB/cm/MHz1.4336/°C as a function of frequency.