An enhancement in the elastic response of two bacterial thermoplastic elastomers, poly(beta-hydroxyoctanoate), a saturated copolymer, and poly(beta-hydroxyoctanoic-co-undecylenic acid), an unsaturated copolymer, was attempted using peroxide crosslinking both with and without multifunctional co-agents. Sol-gel analysis verified that crosslinking had occurred and that crosslinking varied with peroxide type and concentration. A peroxide efficiency model suggested that the olefin group improved the peroxide efficiency and reduced the probability of chain scission. Differential scanning calorimetry showed that crosslinking could eliminate all crystallinity. The elastic response was improved as indicated by a reduced tensile set. In general, the crosslinked materials exhibited a decrease in tensile modulus, and a very low tensile strength and tear resistance.