In this work, innovative jelly tissue-mimicking materials (TMM) have been characterized measuring their specific heat capacity in the temperature range of (10 and 80) °C. These new specimens have improved acoustic characteristics and are promising for improving the efficacy of oncological treatments based on high intensity focused ultrasounds (HIFU). For this reason, it appears very important to have available quantitative measurements of materials thermophysical properties, necessary both for the evaluation of the expected temperature in the focus of HIFU and to validate the numerical software used for planning the adopted therapy. Obtained specific heat capacity have been compared with those available in literature and a detailed uncertainty analysis associated to the obtained results is discussed. Furthermore, preliminary tests have been carried out in the temperature range of (10 and 80) °C for investigating their thermal stability.