Plastics have a high resistance to degradation so they last several years in the environment, generating impacts that make it necessary to find mechanisms that contribute to their decomposition. This study evaluated the biodegradation of plastics such as polyethylene, polystyrene and polypropylene using the Aspergillus flavus fungus, obtained and incubated in the laboratory. The fungus planted in two types of agar (YGC and SDA) was put in contact with the three types of plastic. It was observed that by using two types of agar such as Yeast extract glucose chloramphenicol Agar (YGC) and Sabouraud Dextrose Agar (SDA) for the cultivation of the Aspergillus flavus fungus, there were favorable conditions for the biodegradation of the plastic, leading to better results with YGC agar, since it was possible to obtain a maximum reduction in the polyethylene mass of 23.6% with respect to the initial mass. It was demonstrated that A. flavus degrades polyethylene in greater percentages to other fungi, such as A. niger, and other plastics such as polystyrene and polypropylene. The multifactor ANOVA, used as a dependent variable the decrease in the percentage of mass of the plastic and as factors the type of agar and the type of plastic, showed that the type of agar used, had greater incidence, and was more selective for the Aspergillus flavus agar YGC The result of the multifactor ANOVA accepts the alternative hypothesis: there are differences between YGC and SDA agars in the plastics used in the tests.