This dissertation is a critical analysis of the Radio Days under Brazilian Popular Music` perspectives and those of compositor and singer Dorival Caymmi, which were collected from his work, life and personal testimony through exclusive interviews for biographical motives. Based on a bibliographical research covering the Radio Days and Brazilian Popular Music, not to mention Dorival Caymmi s archive, this investigation intends to discuss - through the case study of the compositor’s nineteen thirty-ninth first success O Que é Que a Baiana tem? - themes such as the radio, phonographic market, cinema, authorship rights, and musical shows, among others, in which the pressures and tensions suffered by the popular artist in his struggles in the labor market, society, politics and the artistic milieu are revealed.