The crystallization kinetics of fractionated samples of polytridecanolactone and polypentadecanolactone have been investigated and compared. The general constitutional repeating unit is [(CH2)(n)CO-O], where n is 12 and 14 for PTDL and PPDL respectively. Equilibrium melting points have been deduced by the Hoffman-Week extrapolation method and found to be close to 364 K and 370 K, respectively. The Lauritzen-Hoffman theory of crystal growth is applied to the data and the extracted nucleation parameters are compared with the ones for polyethylene.