Dyscalculia is considered as the inability to grasp the arithmetical calculations and number concepts. The main goal of this study is to design, develop and standardize Dyscalculia Screening Tool. This Screening Tool is used for students who come under the age level of 8-10 years to screen the mathematical disability. The researcher constructed self-made Dyscalculia Screening Tool with six dimensions namely .Numerical Difficulties, Identification Difficulties, Cognitive difficulties, Problem Solving Difficulties, Reasoning / Logical Difficulties, Understanding Difficulties to identify the students who face the difficulties in basic mathematical and numerical calculations. The pilot study was conducted for 63 students, from3 primary schools in Devakottai Educational District. The tool consists of 34 items which were standardized. The tool is standardized by Cronbach’s alpha reliability value is 0.835 (N=26) and the split-half reliability value is 0.842 (N=26).The final draft contains 26 items as a standardized tool for Screening Students with Dyscalculia. The researcher analyzed the result that the students faced much more difficulties in problem solving ability, understanding the mathematical concepts, logical reasoning and lack of reminiscence capacity. The study suggests that by improving the cognitive aspects of students in their arithmetical learning process the above difficulties can be resolved. [ABSTRACT FROM AUTHOR]