Genre studies have been mainly focused on the rhetorical structure of research papers. However, genre theorists have not systematically studied either relationships among related genres or interlingual studies between genres. The present study aims at describing and comparing the rhetorical and phraseological structures of abstracts in English and Spanish in order to observe how information is rendered in the two languages under analysis. The methodology is descriptively performed on a comparable corpus of abstract in the field of diagnostic imaging and published in well-reputed journals. The authors determine composition strategies by means of a semantic and functional approach so as to establish their similarities and differences in this genre. The results of the research are primarily of help to translators, technical writers and ESP students to better understand some of the discourse aspects of rendering scientific information in both languages.