The utility of the developmental quotient (DQ) obtained with the Psychoeducational Profile Revised (PEP-R) was assessed as a means of estimating cognitive ability in young children with pervasive developmental disorders. Data from the PEP-R were analysed in a sample of 44 children aged from 2.0 to 5.9 years (mean 3.46 ± 1), 13 with an autistic disorder and 31 with a pervasive developmental disorder not otherwise specified. DQ scores were compared with scores from the Leiter International Performance Scale Revised-Visualization and Reasoning Battery (Leiter-R) in the same 44 children. Overall and domain DQs on the PEP-R were significantly correlated with Leiter-R scores. This study suggests that DQ scores obtained from the PEP-R in preschool children with pervasive developmental disorders may be a viable alternative to the Leiter-R as an assessment tool.