The application of biomass, such as starch, cellulose, wood, and sugar, used to substitute fossil resources for the production of plastics, is a widely accepted strategy towards sustainable development. In fact, this way a significant reduction of non renewable energy consumption and carbon dioxide emission is accomplished. In recent years, several typologies of bioplastics were introduced and the most important are those based on cellulosic esters, starch derivatives, polyhydroxybutyrate, polylactic acid, and polycaprolactone. Nowadays, the most important tool to evaluate the environmental impact of a (bio) plastic is the life cycle assessment that determines the overall impact of a plastic on the environment by defining and analyzing several impact categories index like the global warming; the human toxicity; the abiotic depletion; the eutrophication; the acidification; and many others directly related to the production, utilization, and disposal of the considered plastics. The aim of this work is to present a comparison between bioplastics and conventional plastics through the use of the "Life Cycle Assessment" methodology. In particular, the life cycle assessment's Cradle to Grave of shoppers made from Mater-Bi (starch-based plastic) an polyethylene were reported and compared as a case study in order to highlight the strengths and weaknesses of the bioplastics and the conventional plastics.