The authors report on the development of a brief dyslexia screening measure based on revising the 65-item Hong Kong Behaviour Checklist of Specific Learning Difficulties in Reading and Writing. Teachers' ratings of 1063 primary students aged 6-14 years on the behaviour checklist provided data for its psychometric evaluation using traditional measurement and Rasch measurement model analyses. Rasch scaling suggested that the revised 36-item checklist could be regarded as a unidimensional scale that assesses global dyslexic dysfunction, and receiver operating characteristics analysis suggested that a score of 18 could be an optimal cut-off score when it is used as a dyslexia screening measure. The validity of this revised checklist was supported by its substantial and significant correlations with external measures of literacy and cognitive skills. Implications of the findings for the use of adaptive testing to provide an effective procedure for screening are discussed. (Contains 6 tables and 1 figure.)