Purpose To describe the functional activity and the communication-social ability levels of youths with developmental disabilities and to determine whether demographic factors predict these levels. Participants and Methods A mixed, observational and qualitative, study in which parents of students with developmental disabilities were interviewed based on the WeeFIM questions. Both quantitative and qualitative data were analysed. Results Data were collected for 30 youths with mild to severe developmental disabilities with mean age 18.5 ± 2.7 years (19 males). Mean WeeFIM total score was 106.2 ± 10.9, indicating relatively high functional and communication-social ability. No significant difference was observed for the total WeeFIM score between males and females and between adolescents and young adults with developmental disabilities. Main themes emerged from the interviews were: Difficulties with smooth and stable walking, transfers to/from bathtub and stairs. Also, youths are expressing a need for independence in self-care, while relationships with their peers are difficult and problems are primarily solved with help from their parents. Conclusion Despite the high functional and communication-social ability levels of a group of youths with developmental disabilities, parents revealed that youths had certain difficulties. Therapy should address such difficulties to promote independence and participation of these young people in the community.