Children with a significant cognitive and motor developmental delay (SDD) are vulnerable for the development of (future) behavioral and mental health problems. This paper aims to assess the social-emotional functioning of these children, both globally and in various domains. Semi-structured interviews with one or more primary caregiver(s) of 45 children were conducted and analyzed on 13 domains of social-emotional functioning, according to the Scale for Emotional Development - Revised (SED-R). The SED-R scoring system was slightly adapted in the current study in order to elucidate more subtle differences between children. A general delayed social-emotional development was found, with children functioning within different phases across domains and certain domains generally showing higher or lower scores. To capture the emotional needs of children with SDD, a more disaggregated scoring system seems valuable so that both the global level and the level per domain can be taken in consideration in designing interventions.