Mentalization or Reflective Functioning (RF), that is, the ability to reflect upon ones’ own and others behavior in terms of underlying mental states, plays an important role in parenting behavior and children’s socioemotional development. RF has been suggested to be impaired in psychopathology, and thus maternal psychopathology after birth, such as postpartum depression (PPD) and Personality Disorder (PD), may not only affect the mother’s socioemotional functioning but also the development of the child. However, little is known about mentalizing abilities of PPD mothers, and mothers with PPD and comorbid PD. Therefore, the aim of this study was to evaluate RF in women presenting symptoms of PPD (n = 13), and women with PPD symptoms and comorbid PD (n = 14) compared with a nonclinical group (n = 52). Women were interviewed with the Adult Attachment Interview (AAI) before birth (nonclinical group), and 9–12 weeks after birth (clinical groups), and RF was assessed with the Reflective Functioning Scale applied to the AAI. ANCOVA results revealed no significant differences in mean RF abilities among the 3 groups. Possible reasons for the lack of differences in RF between the 3 diagnostic groups are discussed.