With a low production cost and good versatility the polyolefin resins such as polyethylene and polypropylene, have excelled in films and packaging applications. However, despite the good properties and easy processability, these types of films have limitations in adhesion of paints because of their low surface energy. Industrially, there are several techniques used for surface modification of polymeric films. One of the most used industrial techniques to raise the surface energy of films is the treatment by corona discharge. One problem of this technique is the fact that the surface energy of the treated films is not stable and decays as a function of time. This decrease in surface energy is connected with the storage conditions of the films. This work aims to evaluate the influence of environmental conditions in which the films are stored (temperature and relative humidity) in the stability of surface energy as a function of time. This influence will be analyzed for films treated with various potential discharge (70 , 80 and 90 %) and winding speed (1,0 and 1,6 cm s ). The study is based on films of polypropylene (PP). The activities are summarized basically in extruding PP films and submit them to the corona treatment varying the speed and potential discharge during processing and to follow up on the surface energy versus time for movies stored in a controlled location and in an environment not controlled. Among the characterization tests are included: contact angle and surface energy. Preliminary results showed that films stored under controlled temperature and low humidity conditions showed greater stability in surface energy.