Polyhydroxyalkanoates (PHAs) are bio-based polyesters that are natural, renewables, biocompatible and biodegradable while having similar properties to commonly used plastic. However, their industrial production is still more expensive than the petroleum-based one. To make PHAs marketable on a large scale, it is therefore necessary to optimize every single phase of their production. This process must be accompanied by environmental assessments, to verify that PHAs are a greener alternative to conventional plastic. To do this, the best tool currently available is Life Cycle Assessment (LCA). The purpose of this study is to examine the state of the art regarding the application of the LCA methodology to all phases of PHAs production.