Historically the radio ratings in the United States have described audiences by age and sex. In the fall of 1998 Arbitron began collecting information on household income education and presence of children from all respondents. This socioeconomic information is now available to supplement the basic age and sex information. This paper is a preliminary examination of the socioeconomic profiles of the most popular radio formats in the United States using the data from the top twenty-five American markets from the fall 1998 survey. The paper examines format audience characteristics both generally and at the individual market level.