In our previous review (Part I - Material Properties), the chemical, physi-cal and morphological properties, applications and mechanisms of obtain-ing poly (3-hydroxybutyrate) were discussed. PHB is a biologically basedpolymer that presents itself as an ecological option due to its characteristicdegradation before environmental factors and due to the action of microor-ganisms such as algae, fungi and bacteria. In this second review, aspectsrelated to the types of degradation to which this polymer is subjectedand the necessary conditions for its degradation are addressed. Amongthese mechanisms are thermo-degradation, thermo-mechanical degrada-tion, abiotic degradation, photo degradation and biodegradation. It isunderstood that the degradation of PHB can be seen as an advantageousfeature of this material. This review complements the previous one anduses the same terminology.