Children with a significant cognitive and motor developmental delay (SDD) are vulnerable for the development of (future) behavioral and mental health problems. To support children within this target group, knowledge on their social-emotional development is necessary. Therefore, in this paper, an explorative assessment of the changes in the social-emotional functioning of children with SDD over a two-year period was done. Yearly semi-structured interviews with one or more primary caregiver(s) of 25 children were conducted and analyzed on 13 domains of social-emotional functioning, according to an adapted version of the Scale for Emotional Development - Revised (SED-R). This study showed a lot of variation in individual and group patterns of change across the two-year period. Charting the social-emotional development in this target group is challenging and requires further in-depth analysis of individual trajectories as well as more fine-grained and long-term data collection.