The immediate post-partum period offers a valuable opportunity for parental education on various health topics. The aim of this study was to pilot test the feasibility in a tertiary referral center for neonatal care of a post-natal educational intervention (the Diary) designed to provide mothers with basic information concerning newborn care and breastfeeding. Furthermore, we aimed to evaluate its effect on exclusive breastfeeding rates at discharge and at 48 h post-discharge, and on maternal perceived support during hospital stay, compared to standard care. A single-center two-phase interventional study was carried out from 1 December 2018 to 2 June 2019. The Diary was given to mothers enrolled in Phase 2, together with the Nurse–Parent Support Tool (NPST). The Diary–NPST couples analyzed were 269. The Diaries filled out and returned were 62.2%. Overall, mothers rated the information received through the Diary as “clear and comprehensive”. Exclusive breastfeeding rates at discharge resulted in being higher in Phase 1 than in Phase 2 (80.6% vs. 72.5%, p = 0.04), whereas no difference emerged in terms of exclusive breastfeeding rates at 48 h. In both phases, the median NPST total score (4.05) was high. In conclusion, we propose a new instrument of in-hospital post-natal maternal education and, in line with the current literature, we support well-designed written educational materials to promote mothers’ knowledge and satisfaction with post-partum hospital assistance. Further studies that are multicentric and with a longer follow-up period are needed to evaluate the potential impact of the Diary on exclusive breastfeeding duration.