Parental Reflective Functioning and its Relation to Parenting Stress in a Sample with Early Regulatory Disorders Parents' capacity to reflect on their child as a mental agent, is defined as an important competence for the early parent-infant relationship. One way to operationalize this is parental reflective functioning (PRF) that distinguishes between mentalizing and non-mentalizing modes of reflection. Until today PRF has not been investigated in samples of infants/toddlers with early regulatory disorders. Goal of the present study is to investigate PRF by comparing a clinical group with parents of infants/toddlers with early regulatory disorders (N = 98) with a healthy control group (N = 27) and testing if PRF is related to parenting stress, past mental illness of the mother, and stress factors related to pregnancy and birth. A semi-structured clinical interview, the Parenting Stress Index, the Symptom-Check-List-90R-S, the Parental Reflective Functioning Questionnaire, and an anamnestic questionnaire were used. Compared to the control group, mothers of infants/toddlers with early regulatory disorders reported significant more prementalizing. Prementalizing in the total sample was significantly predicted by parenting stress, accounting for 16.3 % of the variance. None of the other independent variables significantly predicted prementalizing. Results are discussed in relation to early regulatory disorders and implications for clinical practice.