Probably, reading is one of the fundamental means of accessing and constructing special ized knowledge, both in academic and professional environments. Then, comprehending written discourse through its diverse disciplinary genres is an essential requirement in the contemporary globalized world, both in paper and digital media. In this context, nowadays, there is scarce research that explores, describes and contrasts the reading habits of university students and professionals in diverse disciplinary fields. Attempting to fill this gap, this study describes the reading habits of a group of 580 university students and a group of 46 professionals in terms of reading on paper and digital, and the discourse genres in two disciplinary areas: philosophy and economics and business. The main results indicate that the subjects of both groups are awareness of the discourse mechanisms of accessing specialized knowledge and declare to employ a wide variety of genres. At the same time, a relative atomization and specialization is observed in a few specific professional genres in both disciplinary domains, in contrast to the great heterogeneity identified in academic discourse. In general terms, the paper medium is preferred for study and learning tasks, both by students and professionals, although students and professionals in business and economics declare that they also prefer digital genres.