This article contextualizes and analyzes the opinions of people who listened to the radio program the Antología Musical de Colombia, as found in the letters they sent to its director, the Colombian musician Oriol Rangel. In those letters, listeners remarked on the values of the "national music" of Colombia, the core of the program, which was drawn from popular genres of Andean music. The article shows the convergence of commercial radio networks, the national record industry, specialized criticism and radio audiences in the mid-20th century in Colombia. The opinions of the listeners, which are recreated on the basis of novel original sources, reveal their listening habits, aesthetic preferences and anxiety about what they regarded as the loss of "national music".