The vast majority of breastfeeding mothers in Western countries have routine access to multimedia and Internet resources at home. The aim of this study was to assess the effectiveness of a CD-ROM-based intervention in increasing the rates of breastfeeding. We conducted a pre- and post-intervention study involving four control and four intervention maternity units in France. All breastfeeding mothers in intervention units were given a CD-ROM-based program addressing various breastfeeding topics. The primary outcome was any breastfeeding at 4 weeks assessed by follow-up telephone interview. The secondary outcomes included breastfeeding duration, breastfeeding difficulties after discharge and satisfaction with the breastfeeding experience. The rates of any breastfeeding at 4 weeks varied from 88.6% (209/236) to 87.9% (211/240) and from 86.0% (222/258) to 88.0% (228/259) for mothers enrolled in intervention and control maternity units, respectively (P for interaction=0.54). The hazard of breastfeeding discontinuation for mothers enrolled in intervention units did not vary significantly across study periods after adjusting for education level, epidural anaesthesia, breastfeeding assessment score and return to work (P for interaction=0.18). The rates of breastfeeding at 4 weeks remained unchanged when restricting the analysis to the mothers who actually received (87.8% [173/197]) or used [88.2% (105/119)] the CD-ROM during the post-intervention period. No significant differences were found in secondary outcomes between the two study groups. A CD-ROM-based intervention for breastfeeding mothers provides no additional benefit to usual post-natal care. Further study is needed to assess the effectiveness of multimedia packages as part of more intensive multifaceted interventions.