The synthesis of a series of u-hydroxyfatty acid (u-OHFA) monomers and their methyl ester derivatives (Me-u-OHFA) from mono-unsaturated fatty acids and alcohols via ozonolysis-reduction/crossmetathesis reactions is described. Melt polycondensation of the monomers yielded thermoplastic poly(u-hydroxyfatty acid)s [-(CH 2 ) n -COO-] x with medium (n ¼ 8 and 12) and long (n ¼ 17) repeating monomer units. The u-OHFAs and Me-u-OHFAs were all obtained in good yield ($80%) and purity ($97%) as established by 1 H NMR, Fourier Transform infra-red spectroscopy (FT-IR), mass spectroscopy (ESI-MS) and high performance liquid chromatography (HPLC) analyses. The average molecular size (M n ) and distribution (PDI) of the poly(u-hydroxyfatty acid)s (P(u-OHFA)s) and poly(u-hydroxyfatty ester)s (P(Me-u-OHFA)s) as determined by GPC varied with organo-metallic Ti(IV) isopropoxide [Ti(OiPr) 4 ] polycondensation catalyst amount, reaction time and temperature. An optimization of the polymerization process provided P(u-OHFA)s and P(Me-u-OHFA)s with M n and PDI values desirable for high end applications. Co-polymerization of the long chain (n ¼ 12) and medium chain (n ¼ 8) Me-u-OHFAs by melt polycondensation yielded poly(u-hydroxy tridecanoate/u-hydroxy nonanoate) random co-polyesters (M n ¼ 11 000-18 500 g mol À1 ) with varying molar compositions.