MSc (Occupational Therapy), Faculty of Health Sciences, University of the Witwatersrand / As there are no occupation based outcome measures evaluating the effect of occupational therapy in the pre-school child with an Autism Spectrum Disorder (ASD) an Occupational Performance Questionnaire (OPQ) was developed to address this. The OPQ was tested for content validity and reliability before a 12 month intervention study to establish construct validity and response to change in children with ASD receiving Occupational Therapy using a Sensory Integration frame of reference (OT-SI) was done. The results of 19 subjects on the OPQ were compared with the results on two other standardised measures -the Short Sensory Profile (SSP), and Parenting Stress Index (PSI-SF) at six monthly intervals. Convergent validity between family impact on the OPQ and the PSI-SF was moderate but for occupation performance on the OPQ and the SSP it changed from negligible to moderate over 12 months. The OPQ is responsive to change as correlations between improvements in the three outcome measures were moderate. The OPQ was found to still need attention in terms of item reliability and validity.