The components of biodiesel derived from coconut oil or babassu oil such as ethyl caprylate and ethyl caprate are studied. The experimental speeds of sound in ethyl caprylate were reported at p = (0.1 to 101.32) MPa and at T (292.90 to 318.32) K and in ethyl caprate at p = (0.1 to 101.32) MPa and at T = (292.90 to 318.28) K together with the experimental densities at 0.1 MPa for ethyl caprylate at T = (278.15 to 358.15) K and for ethyl caprate at T = (283.15 to 353.14) K as well as heat capacities were reported at 0.1 MPa for ethyl capxylate at T = (285.01 to 343.78) K and for ethyl caprate at T = (286.16 to 341.11) K. The density, adiabatic and isothermal cornpressibilities, heat capacity, isobaric thermal expansion, and internal pressure at elevated pressures and temperatures were calculated from the experimental res in the way described by Davis and Gordon (J. Chem. Phys. 1967, 46, 2650-2660) with the aim of studying the effect of changing of the carbon chain length from ethyl caprylate to ethyl caprate on pressure and temperature dependence of above-mentioned properties. Moreover, densities of ethyl caprylate and ethyl caprate were compared with densities of ethyl laurate and ethyl myristate to improve intersection of their isotherms.