Purpose To investigate the nature and extent of oral language difficulties encountered by adults who are functionally illiterate. Method Fifty-two men and women identified as functionally illiterate, together with a group of control individuals of comparable age, sex, and socioprofessional background, produced a narrative intended for an absent recipient based on a sequence of pictures featuring a cast of 3 protagonists. All narratives were transcribed in their entirety and coded in terms of linguistic features and discourse organization. Results As a group, the participants who were illiterate had great difficulty handling morphosyntactic rules, referential cohension, and the narrative schema. Furthermore, a qualitative analysis highlighted considerable interindividual variability in narrative styles, reflecting different types of difficulties. Conclusions Individuals who have not succeeded in learning to read also have impaired oral language abilities. This may affect different aspects of communication skills to a greater or lesser extent. These results have implications for teaching written language to adult learners.