The heat capacity of ethyl undecanoate was measured between 110 K and 365 K; the compound crystallized in a metastable form, which recrystallized slowly to the stable crystalline state during heating. The triple-point temperature of the stable form was found to be (259.17 +/- 0.04) K, and the enthalpy of fusion was (36.1 +/- 0.1) kJ center dot mol(-1). The purity calculated from the fractional melting curve was 97.5 mol %. The metastable form crystallized at 251.3 K. The heat capacity of ethyl tridecanoate was measured between 175 K and 320 K; the compound also crystallized in a metastable form, which recrystallized during heating to the stable form. The triple-point temperature was found to be (272.4 +/- 0.1) K, and the enthalpy of fusion was (40.7 +/- 0.1) kJ center dot mol(-1).