This article explores the relationship between maternal reflective functioning (MRF) and Reactive Attachment Disorder (RAD) from both a theoretical and clinical perspective. A new scoring system that evaluates the predominance in the mother of prementalizing modes of psychic functioning (psychic equivalence and pretend mode) has been developed and applied to the Parent Development Interview-Revised. The theoretical foundations of this system are presented and its scoring criteria are briefly described. The protocols of two mothers whose children suffer from RAD are analyzed using the RF scoring system (Slade, Bernbach et al., 2005) and the new scoring system developed for this study (Leroux & Terradas, 2012) in order to demonstrate their complementary use. Some theoretical and clinical thoughts about the impact of MRF on the development of RAD are revealed. This being a small-scale exploratory study, further research is needed to establish the psychometric properties of this new coding system.