autism spectrum disorders (asd) are characterized by marked deficits in socialization. along this spectrum, however, intellectual functioning varies. individuals with low-functioning autism typically function in the moderate mental retardation range (iq between 35-50), while higher-functioning individuals have average or above-average iqs. because daily living skills (e.g., socialization) and cognitive functioning are important considerations in the diagnosis of autism spectrum disorders, much research has focussed upon these areas in comparing asd individuals with those individuals with developmental disabilities (dd). however, minimal research focus has been allotted to the strengths o f individuals diagnosed with these disorders as a differentiating feature. specifically, very few studies have examined the connection between strengths, behavioural difficulties and adaptive functioning within these diagnostic groups. comparison of individuals with these disorders with a sample of individuals with developmental disabilities may further strengthen the distinctness o f these conditions based upon behavioural difficulties, iq and adaptive functioning, as well as provide evidence o f strengths potentially predictive o f adaptive behaviour. thus, the purpose of this investigation was to have primary caregivers (e.g., parents/guardians) complete two strength-based questionnaires, an adaptive measure and a behavioural checklist on adolescents with four different diagnoses. these diagnoses included low-functioning autism (iq below 70), high-functioning autism (iq 70 and above), asperger syndrome, developmental disability, and a control group with no formal diagnosis. the overall focus of this thesis was exploratory, however, some specific hypotheses were also tested. results indicated different and unique profiles for each group in terms of strengths, adaptive functioning, and behavioural difficulties. moreover, individuals with low-functioning autism exhibited similar profiles to those with developmental disability, and individuals with high-functioning autism exhibited profiles similar to those with asperger syndrome. specifically, individuals with low-functioning autism and developmental disability exhibited fewer strengths and adaptive functioning skills and greater behavioural difficulties, while those with high-functioning autism and asperger syndrome displayed greater strengths and adaptive functioning skills and fewer behavioural difficulties. normal individuals also differed from the diagnostic groups in this respect, in that they exhibited far more strengths and adaptive functioning skills and fewer behavioural difficulties when compared to the diagnostic groups.