In this study, we determine the effect of temperature and frequency on the acoustic properties of konjac glucomannan (KGM)-agar gels to confirm their compatibilities as tissue mimicking materials (TMMs). The acoustic properties of four samples; A (KGM-0.10 g agar), B (KGM-0.20 g agar), C (KGM-0.30 g agar) and D (KGM-0.40 g agar) were measured using pulse echo immersion technique. Findings indicated that the longitudinal velocities of all samples were increased while their attenuation coefficients were decreased as the temperature increased from 27.0 to 37.0°C. It also showed that the phase velocities of all samples were independent to frequency but their attenuation coefficients were increased as the frequency increased from 4.0 to 6.0 MHz. KGM-agar gels are compatible as soft TMMs since their acoustic properties are comparable with the acoustic properties of soft tissue.