The purpose of this study is to design and develop Dyscalculia Checklist Instrument (DCI) for dyscalculic pupils in primary schools. Dyscalculia is a learning disability in mathematics. Unlike dyslexia, there is still no checklist available in our country to detect these dyscalculic pupils. If they are not being detected, these pupils will continue being left out and labelled, with no proper intervention or diagnosis given to them. This study will employ Design and Development Research (DDR) approach. During phase one, needs analysis will be carried out to 90 teachers and 90 parents. This is to identify whether there is a need to develop a checklist for dyscalculic pupils in primary schools. During phase two, Fuzzy Delphi Method (FDM) will be carried out by inviting 11 experts in the fields of dyscalculia, special education, and instrumentation. During phase three, Nominal Group Technique (NGT) will be implemented. The experts will vote and rank for the constructs and items in DCI. Purposive sampling method will be employed in this study. The data will be analysed using descriptive and inferential statistics. T-test will be used to compare the data of needs to develop DCI between teachers and parents. ANOVA will be used to compare the data of needs to develop DCI between Malay-Medium National School (SK), National-Type Chinese Primary School (SJKC), and National-Type Tamil Primary School (SJKT). Then, the researcher will obtain the threshold, d value and experts’ consensus value to design, develop and evaluate the constructs and items in DCI.